diff --git a/catchain/catchain-receiver.cpp b/catchain/catchain-receiver.cpp
index edef90659..a6160383c 100644
--- a/catchain/catchain-receiver.cpp
+++ b/catchain/catchain-receiver.cpp
@@ -526,10 +526,12 @@ void CatChainReceiverImpl::start_up() {
   for (td::uint32 i = 0; i < get_sources_cnt(); i++) {
     root_keys.emplace(get_source(i)->get_hash(), OVERLAY_MAX_ALLOWED_PACKET_SIZE);
   }
-  td::actor::send_closure(overlay_manager_, &overlay::Overlays::create_private_overlay,
+  overlay::OverlayOptions overlay_options;
+  overlay_options.broadcast_speed_multiplier_ = opts_.broadcast_speed_multiplier;
+  td::actor::send_closure(overlay_manager_, &overlay::Overlays::create_private_overlay_ex,
                           get_source(local_idx_)->get_adnl_id(), overlay_full_id_.clone(), std::move(ids),
                           make_callback(), overlay::OverlayPrivacyRules{0, 0, std::move(root_keys)},
-                          R"({ "type": "catchain" })");
+                          R"({ "type": "catchain" })", std::move(overlay_options));
 
   CHECK(root_block_);
 
diff --git a/crypto/block/block.cpp b/crypto/block/block.cpp
index 302a2aa46..452d78a29 100644
--- a/crypto/block/block.cpp
+++ b/crypto/block/block.cpp
@@ -360,7 +360,6 @@ MsgProcessedUptoCollection::MsgProcessedUptoCollection(ton::ShardIdFull _owner,
     z.shard = key.get_uint(64);
     z.mc_seqno = (unsigned)((key + 64).get_uint(32));
     z.last_inmsg_lt = value.write().fetch_ulong(64);
-    // std::cerr << "ProcessedUpto shard " << std::hex << z.shard << std::dec << std::endl;
     return value.write().fetch_bits_to(z.last_inmsg_hash) && z.shard && ton::shard_contains(owner.shard, z.shard);
   });
 }
@@ -862,8 +861,10 @@ td::Status ShardState::unpack_out_msg_queue_info(Ref<vm::Cell> out_msg_queue_inf
   out_msg_queue_ =
       std::make_unique<vm::AugmentedDictionary>(std::move(qinfo.out_queue), 352, block::tlb::aug_OutMsgQueue);
   if (verbosity >= 3 * 1) {
-    LOG(DEBUG) << "unpacking ProcessedUpto of our previous block " << id_.to_str();
-    block::gen::t_ProcessedInfo.print(std::cerr, qinfo.proc_info);
+    FLOG(DEBUG) {
+      sb << "unpacking ProcessedUpto of our previous block " << id_.to_str();
+      block::gen::t_ProcessedInfo.print(sb, qinfo.proc_info);
+    };
   }
   if (!block::gen::t_ProcessedInfo.validate_csr(1024, qinfo.proc_info)) {
     return td::Status::Error(
diff --git a/crypto/block/mc-config.cpp b/crypto/block/mc-config.cpp
index 148819136..48a2d6137 100644
--- a/crypto/block/mc-config.cpp
+++ b/crypto/block/mc-config.cpp
@@ -163,8 +163,11 @@ td::Status ConfigInfo::unpack() {
   }
   gen::McStateExtra::Record extra_info;
   if (!tlb::unpack_cell(state_extra_root_, extra_info)) {
-    vm::load_cell_slice(state_extra_root_).print_rec(std::cerr);
-    block::gen::t_McStateExtra.print_ref(std::cerr, state_extra_root_);
+    FLOG(WARNING) {
+      sb << "state extra information is invalid: ";
+      vm::load_cell_slice(state_extra_root_).print_rec(sb);
+      block::gen::t_McStateExtra.print_ref(sb, state_extra_root_);
+    };
     return td::Status::Error("state extra information is invalid");
   }
   gen::ValidatorInfo::Record validator_info;
@@ -1067,7 +1070,6 @@ Ref<McShardHash> ShardConfig::get_shard_hash(ton::ShardIdFull id, bool exact) co
   ton::ShardIdFull true_id;
   vm::CellSlice cs;
   if (get_shard_hash_raw(cs, id, true_id, exact)) {
-    // block::gen::t_ShardDescr.print(std::cerr, vm::CellSlice{cs});
     return McShardHash::unpack(cs, true_id);
   } else {
     return {};
@@ -1637,8 +1639,10 @@ bool ShardConfig::set_shard_info(ton::ShardIdFull shard, Ref<vm::Cell> value) {
   if (!gen::t_BinTree_ShardDescr.validate_ref(1024, value)) {
     LOG(ERROR) << "attempting to store an invalid (BinTree ShardDescr) at shard configuration position "
                << shard.to_str();
-    gen::t_BinTree_ShardDescr.print_ref(std::cerr, value);
-    vm::load_cell_slice(value).print_rec(std::cerr);
+    FLOG(WARNING) {
+      gen::t_BinTree_ShardDescr.print_ref(sb, value);
+      vm::load_cell_slice(value).print_rec(sb);
+    };
     return false;
   }
   auto root = shard_hashes_dict_->lookup_ref(td::BitArray<32>{shard.workchain});
diff --git a/crypto/block/output-queue-merger.cpp b/crypto/block/output-queue-merger.cpp
index aa425f6b8..7d258cfe7 100644
--- a/crypto/block/output-queue-merger.cpp
+++ b/crypto/block/output-queue-merger.cpp
@@ -138,7 +138,6 @@ bool OutputQueueMerger::add_root(int src, Ref<vm::Cell> outmsg_root) {
   if (outmsg_root.is_null()) {
     return true;
   }
-  //block::gen::HashmapAug{352, block::gen::t_EnqueuedMsg, block::gen::t_uint64}.print_ref(std::cerr, outmsg_root);
   auto kv = std::make_unique<MsgKeyValue>(src, std::move(outmsg_root));
   if (kv->replace_by_prefix(common_pfx.cbits(), common_pfx_len)) {
     heap.push_back(std::move(kv));
diff --git a/crypto/block/transaction.cpp b/crypto/block/transaction.cpp
index ba50c581d..46c696f51 100644
--- a/crypto/block/transaction.cpp
+++ b/crypto/block/transaction.cpp
@@ -446,8 +446,10 @@ bool Account::unpack(Ref<vm::CellSlice> shard_account, ton::UnixTime now, bool s
     return false;
   }
   if (verbosity > 2) {
-    shard_account->print_rec(std::cerr, 2);
-    block::gen::t_ShardAccount.print(std::cerr, *shard_account);
+    FLOG(INFO) {
+      shard_account->print_rec(sb, 2);
+      block::gen::t_ShardAccount.print(sb, shard_account);
+    };
   }
   block::gen::ShardAccount::Record acc_info;
   if (!(block::tlb::t_ShardAccount.validate_csr(shard_account) && tlb::unpack_exact(shard_account.write(), acc_info))) {
@@ -737,9 +739,11 @@ bool Transaction::unpack_input_msg(bool ihr_delivered, const ActionPhaseConfig*
     return false;
   }
   if (verbosity > 2) {
-    fprintf(stderr, "unpacking inbound message for a new transaction: ");
-    block::gen::t_Message_Any.print_ref(std::cerr, in_msg);
-    load_cell_slice(in_msg).print_rec(std::cerr);
+    FLOG(INFO) {
+      sb << "unpacking inbound message for a new transaction: ";
+      block::gen::t_Message_Any.print_ref(sb, in_msg);
+      load_cell_slice(in_msg).print_rec(sb);
+    };
   }
   auto cs = vm::load_cell_slice(in_msg);
   int tag = block::gen::t_CommonMsgInfo.get_tag(cs);
@@ -1550,11 +1554,13 @@ bool Transaction::run_precompiled_contract(const ComputePhaseConfig& cfg, precom
     cp.actions = impl.get_c5();
     int out_act_num = output_actions_count(cp.actions);
     if (verbosity > 2) {
-      std::cerr << "new smart contract data: ";
-      bool can_be_special = true;
-      load_cell_slice_special(cp.new_data, can_be_special).print_rec(std::cerr);
-      std::cerr << "output actions: ";
-      block::gen::OutList{out_act_num}.print_ref(std::cerr, cp.actions);
+      FLOG(INFO) {
+        sb << "new smart contract data: ";
+        bool can_be_special = true;
+        load_cell_slice_special(cp.new_data, can_be_special).print_rec(sb);
+        sb << "output actions: ";
+        block::gen::OutList{out_act_num}.print_ref(sb, cp.actions);
+      };
     }
   }
   cp.mode = 0;
@@ -1619,7 +1625,6 @@ bool Transaction::prepare_compute_phase(const ComputePhaseConfig& cfg) {
   if (in_msg_state.not_null()) {
     LOG(DEBUG) << "HASH(in_msg_state) = " << in_msg_state->get_hash().bits().to_hex(256)
                << ", account_state_hash = " << account.state_hash.to_hex();
-    // vm::load_cell_slice(in_msg_state).print_rec(std::cerr);
   } else {
     LOG(DEBUG) << "in_msg_state is null";
   }
@@ -1775,11 +1780,13 @@ bool Transaction::prepare_compute_phase(const ComputePhaseConfig& cfg) {
     cp.actions = vm.get_committed_state().c5;   // c5 -> action list
     int out_act_num = output_actions_count(cp.actions);
     if (verbosity > 2) {
-      std::cerr << "new smart contract data: ";
-      bool can_be_special = true;
-      load_cell_slice_special(cp.new_data, can_be_special).print_rec(std::cerr);
-      std::cerr << "output actions: ";
-      block::gen::OutList{out_act_num}.print_ref(std::cerr, cp.actions);
+      FLOG(INFO) {
+        sb << "new smart contract data: ";
+        bool can_be_special = true;
+        load_cell_slice_special(cp.new_data, can_be_special).print_rec(sb);
+        sb << "output actions: ";
+        block::gen::OutList{out_act_num}.print_ref(sb, cp.actions);
+      };
     }
   }
   cp.mode = 0;
@@ -2725,14 +2732,18 @@ int Transaction::try_action_send_msg(const vm::CellSlice& cs0, ActionPhase& ap,
   }
   if (!block::gen::t_Message_Any.validate_ref(new_msg)) {
     LOG(ERROR) << "generated outbound message is not a valid (Message Any) according to automated check";
-    block::gen::t_Message_Any.print_ref(std::cerr, new_msg);
-    vm::load_cell_slice(new_msg).print_rec(std::cerr);
+    FLOG(INFO) {
+      block::gen::t_Message_Any.print_ref(sb, new_msg);
+      vm::load_cell_slice(new_msg).print_rec(sb);
+    };
     collect_fine();
     return -1;
   }
   if (verbosity > 2) {
-    std::cerr << "converted outbound message: ";
-    block::gen::t_Message_Any.print_ref(std::cerr, new_msg);
+    FLOG(INFO) {
+      sb << "converted outbound message: ";
+      block::gen::t_Message_Any.print_ref(sb, new_msg);
+    };
   }
 
   ap.msgs_created++;
@@ -3045,8 +3056,10 @@ bool Transaction::prepare_bounce_phase(const ActionPhaseConfig& cfg) {
   }
   CHECK(cb.finalize_to(bp.out_msg));
   if (verbosity > 2) {
-    LOG(INFO) << "generated bounced message: ";
-    block::gen::t_Message_Any.print_ref(std::cerr, bp.out_msg);
+    FLOG(INFO) {
+      sb << "generated bounced message: ";
+      block::gen::t_Message_Any.print_ref(sb, bp.out_msg);
+    };
   }
   out_msgs.push_back(bp.out_msg);
   bp.ok = true;
@@ -3167,11 +3180,13 @@ bool Transaction::compute_state() {
       auto frozen_state = cb2.finalize();
       frozen_hash = frozen_state->get_hash().bits();
       if (verbosity >= 3 * 1) {  // !!!DEBUG!!!
-        std::cerr << "freezing state of smart contract: ";
-        block::gen::t_StateInit.print_ref(std::cerr, frozen_state);
-        CHECK(block::gen::t_StateInit.validate_ref(frozen_state));
-        CHECK(block::tlb::t_StateInit.validate_ref(frozen_state));
-        std::cerr << "with hash " << frozen_hash.to_hex() << std::endl;
+        FLOG(INFO) {
+          sb << "freezing state of smart contract: ";
+          block::gen::t_StateInit.print_ref(sb, frozen_state);
+          CHECK(block::gen::t_StateInit.validate_ref(frozen_state));
+          CHECK(block::tlb::t_StateInit.validate_ref(frozen_state));
+          sb << "with hash " << frozen_hash.to_hex();
+        };
       }
     }
     new_code.clear();
@@ -3229,8 +3244,10 @@ bool Transaction::compute_state() {
   CHECK(cb.append_data_cell_bool(std::move(storage)));
   new_total_state = cb.finalize();
   if (verbosity > 2) {
-    std::cerr << "new account state: ";
-    block::gen::t_Account.print_ref(std::cerr, new_total_state);
+    FLOG(INFO) {
+      sb << "new account state: ";
+      block::gen::t_Account.print_ref(sb, new_total_state);
+    };
   }
   CHECK(block::tlb::t_Account.validate_ref(new_total_state));
   return true;
@@ -3322,22 +3339,28 @@ bool Transaction::serialize() {
       return false;
   }
   if (verbosity >= 3 * 1) {
-    std::cerr << "new transaction: ";
-    block::gen::t_Transaction.print_ref(std::cerr, root);
-    vm::load_cell_slice(root).print_rec(std::cerr);
+    FLOG(INFO) {
+      sb << "new transaction: ";
+      block::gen::t_Transaction.print_ref(sb, root);
+      vm::load_cell_slice(root).print_rec(sb);
+    };
   }
 
   if (!block::gen::t_Transaction.validate_ref(4096, root)) {
     LOG(ERROR) << "newly-generated transaction failed to pass automated validation:";
-    vm::load_cell_slice(root).print_rec(std::cerr);
-    block::gen::t_Transaction.print_ref(std::cerr, root);
+    FLOG(INFO) {
+      vm::load_cell_slice(root).print_rec(sb);
+      block::gen::t_Transaction.print_ref(sb, root);
+    };
     root.clear();
     return false;
   }
   if (!block::tlb::t_Transaction.validate_ref(4096, root)) {
     LOG(ERROR) << "newly-generated transaction failed to pass hand-written validation:";
-    vm::load_cell_slice(root).print_rec(std::cerr);
-    block::gen::t_Transaction.print_ref(std::cerr, root);
+    FLOG(INFO) {
+      vm::load_cell_slice(root).print_rec(sb);
+      block::gen::t_Transaction.print_ref(sb, root);
+    };
     root.clear();
     return false;
   }
diff --git a/crypto/tl/tlblib.cpp b/crypto/tl/tlblib.cpp
index 05ea8e1c2..de5a483c6 100644
--- a/crypto/tl/tlblib.cpp
+++ b/crypto/tl/tlblib.cpp
@@ -196,6 +196,13 @@ bool TLB::print_ref(std::ostream& os, Ref<vm::Cell> cell_ref, int indent, int re
   return pp.fail_unless(print_ref(pp, std::move(cell_ref)));
 }
 
+bool TLB::print_ref(td::StringBuilder& sb, Ref<vm::Cell> cell_ref, int indent, int rec_limit) const {
+  std::ostringstream ss;
+  auto result = print_ref(ss, std::move(cell_ref), indent, rec_limit);
+  sb << ss.str();
+  return result;
+}
+
 std::string TLB::as_string_skip(vm::CellSlice& cs, int indent) const {
   std::ostringstream os;
   print_skip(os, cs, indent);
diff --git a/crypto/tl/tlblib.hpp b/crypto/tl/tlblib.hpp
index a6350ece3..c10049a93 100644
--- a/crypto/tl/tlblib.hpp
+++ b/crypto/tl/tlblib.hpp
@@ -246,7 +246,14 @@ class TLB {
   bool print(std::ostream& os, Ref<vm::CellSlice> cs_ref, int indent = 0, int rec_limit = 0) const {
     return print(os, *cs_ref, indent, rec_limit);
   }
+  bool print(td::StringBuilder& sb, Ref<vm::CellSlice> cs_ref, int indent = 0, int rec_limit = 0) const {
+    std::ostringstream ss;
+    auto result = print(ss, *cs_ref, indent, rec_limit);
+    sb << ss.str();
+    return result;
+  }
   bool print_ref(std::ostream& os, Ref<vm::Cell> cell_ref, int indent = 0, int rec_limit = 0) const;
+  bool print_ref(td::StringBuilder& sb, Ref<vm::Cell> cell_ref, int indent = 0, int rec_limit = 0) const;
   bool print_ref(int rec_limit, std::ostream& os, Ref<vm::Cell> cell_ref, int indent = 0) const {
     return print_ref(os, std::move(cell_ref), indent, rec_limit);
   }
diff --git a/crypto/vm/cells/CellSlice.cpp b/crypto/vm/cells/CellSlice.cpp
index 4d8c3c5ad..9cd3e931a 100644
--- a/crypto/vm/cells/CellSlice.cpp
+++ b/crypto/vm/cells/CellSlice.cpp
@@ -1026,6 +1026,13 @@ bool CellSlice::print_rec(std::ostream& os, int indent) const {
   return print_rec(os, &limit, indent);
 }
 
+bool CellSlice::print_rec(td::StringBuilder& sb, int indent) const {
+  std::ostringstream ss;
+  auto result = print_rec(ss, indent);
+  sb << ss.str();
+  return result;
+}
+
 bool CellSlice::print_rec(int limit, std::ostream& os, int indent) const {
   return print_rec(os, &limit, indent);
 }
diff --git a/crypto/vm/cells/CellSlice.h b/crypto/vm/cells/CellSlice.h
index 33fad7410..ecce30f5c 100644
--- a/crypto/vm/cells/CellSlice.h
+++ b/crypto/vm/cells/CellSlice.h
@@ -257,6 +257,7 @@ class CellSlice : public td::CntObject {
   void dump(std::ostream& os, int level = 0, bool endl = true) const;
   void dump_hex(std::ostream& os, int mode = 0, bool endl = false) const;
   bool print_rec(std::ostream& os, int indent = 0) const;
+  bool print_rec(td::StringBuilder& sb, int indent = 0) const;
   bool print_rec(std::ostream& os, int* limit, int indent = 0) const;
   bool print_rec(int limit, std::ostream& os, int indent = 0) const;
   void error() const {
diff --git a/overlay/overlay-fec.cpp b/overlay/overlay-fec.cpp
index b29fce229..817d3b7c2 100644
--- a/overlay/overlay-fec.cpp
+++ b/overlay/overlay-fec.cpp
@@ -32,7 +32,7 @@ void OverlayOutboundFecBroadcast::alarm() {
                             fec_type_.size(), flags_, std::move(X.data), X.id, fec_type_, date_);
   }
 
-  alarm_timestamp() = td::Timestamp::in(0.010);
+  alarm_timestamp() = td::Timestamp::in(delay_);
 
   if (seqno_ >= to_send_) {
     stop();
@@ -46,8 +46,9 @@ void OverlayOutboundFecBroadcast::start_up() {
 
 OverlayOutboundFecBroadcast::OverlayOutboundFecBroadcast(td::BufferSlice data, td::uint32 flags,
                                                          td::actor::ActorId<OverlayImpl> overlay,
-                                                         PublicKeyHash local_id)
+                                                         PublicKeyHash local_id, double speed_multiplier)
     : flags_(flags) {
+  delay_ /= speed_multiplier;
   CHECK(data.size() <= (1 << 27));
   local_id_ = local_id;
   overlay_ = std::move(overlay);
@@ -63,9 +64,10 @@ OverlayOutboundFecBroadcast::OverlayOutboundFecBroadcast(td::BufferSlice data, t
 }
 
 td::actor::ActorId<OverlayOutboundFecBroadcast> OverlayOutboundFecBroadcast::create(
-    td::BufferSlice data, td::uint32 flags, td::actor::ActorId<OverlayImpl> overlay, PublicKeyHash local_id) {
-  return td::actor::create_actor<OverlayOutboundFecBroadcast>(td::actor::ActorOptions().with_name("bcast"),
-                                                              std::move(data), flags, overlay, local_id)
+    td::BufferSlice data, td::uint32 flags, td::actor::ActorId<OverlayImpl> overlay, PublicKeyHash local_id,
+    double speed_multiplier) {
+  return td::actor::create_actor<OverlayOutboundFecBroadcast>(
+             td::actor::ActorOptions().with_name("bcast"), std::move(data), flags, overlay, local_id, speed_multiplier)
       .release();
 }
 
diff --git a/overlay/overlay-fec.hpp b/overlay/overlay-fec.hpp
index a9cc36346..b72e830ea 100644
--- a/overlay/overlay-fec.hpp
+++ b/overlay/overlay-fec.hpp
@@ -37,6 +37,7 @@ class OverlayOutboundFecBroadcast : public td::actor::Actor {
   PublicKeyHash local_id_;
   Overlay::BroadcastDataHash data_hash_;
   td::uint32 flags_ = 0;
+  double delay_ = 0.010;
   td::int32 date_;
   std::unique_ptr<td::fec::Encoder> encoder_;
   td::actor::ActorId<OverlayImpl> overlay_;
@@ -45,9 +46,9 @@ class OverlayOutboundFecBroadcast : public td::actor::Actor {
  public:
   static td::actor::ActorId<OverlayOutboundFecBroadcast> create(td::BufferSlice data, td::uint32 flags,
                                                                 td::actor::ActorId<OverlayImpl> overlay,
-                                                                PublicKeyHash local_id);
+                                                                PublicKeyHash local_id, double speed_multiplier = 1.0);
   OverlayOutboundFecBroadcast(td::BufferSlice data, td::uint32 flags, td::actor::ActorId<OverlayImpl> overlay,
-                              PublicKeyHash local_id);
+                              PublicKeyHash local_id, double speed_multiplier = 1.0);
 
   void alarm() override;
   void start_up() override;
diff --git a/overlay/overlay.cpp b/overlay/overlay.cpp
index 429c6a9c8..30a40b1cf 100644
--- a/overlay/overlay.cpp
+++ b/overlay/overlay.cpp
@@ -63,7 +63,7 @@ td::actor::ActorOwn<Overlay> Overlay::create_private(
   return td::actor::create_actor<OverlayImpl>(
       overlay_actor_name(overlay_id), keyring, adnl, manager, dht_node, local_id, std::move(overlay_id),
       OverlayType::FixedMemberList, std::move(nodes), std::vector<PublicKeyHash>(), OverlayMemberCertificate{},
-      std::move(callback), std::move(rules), std::move(scope));
+      std::move(callback), std::move(rules), std::move(scope), std::move(opts));
 }
 
 td::actor::ActorOwn<Overlay> Overlay::create_semiprivate(
@@ -99,6 +99,7 @@ OverlayImpl::OverlayImpl(td::actor::ActorId<keyring::Keyring> keyring, td::actor
   overlay_id_ = id_full_.compute_short_id();
   frequent_dht_lookup_ = opts_.frequent_dht_lookup_;
   peer_list_.local_member_flags_ = opts_.local_overlay_member_flags_;
+  opts_.broadcast_speed_multiplier_ = std::max(opts_.broadcast_speed_multiplier_, 1e-9);
 
   VLOG(OVERLAY_INFO) << this << ": creating";
 
@@ -490,7 +491,8 @@ void OverlayImpl::send_broadcast_fec(PublicKeyHash send_as, td::uint32 flags, td
     VLOG(OVERLAY_WARNING) << "broadcast source certificate is invalid";
     return;
   }
-  OverlayOutboundFecBroadcast::create(std::move(data), flags, actor_id(this), send_as);
+  OverlayOutboundFecBroadcast::create(std::move(data), flags, actor_id(this), send_as,
+                                      opts_.broadcast_speed_multiplier_);
 }
 
 void OverlayImpl::print(td::StringBuilder &sb) {
diff --git a/overlay/overlays.h b/overlay/overlays.h
index c0385fc77..5eb63b13f 100644
--- a/overlay/overlays.h
+++ b/overlay/overlays.h
@@ -269,6 +269,7 @@ struct OverlayOptions {
   td::uint32 nodes_to_send_ = 4;
   td::uint32 propagate_broadcast_to_ = 5;
   td::uint32 default_permanent_members_flags_ = 0;
+  double broadcast_speed_multiplier_ = 1.0;
 };
 
 class Overlays : public td::actor::Actor {
diff --git a/tdutils/td/utils/Time.h b/tdutils/td/utils/Time.h
index ece822d41..c7795ae4a 100644
--- a/tdutils/td/utils/Time.h
+++ b/tdutils/td/utils/Time.h
@@ -128,6 +128,10 @@ inline Timestamp &operator+=(Timestamp &a, double b) {
   return a;
 }
 
+inline double operator-(const Timestamp &a, const Timestamp &b) {
+  return a.at() - b.at();
+}
+
 template <class StorerT>
 void store(const Timestamp &timestamp, StorerT &storer) {
   storer.store_binary(timestamp.at() - Time::now() + Clocks::system());
diff --git a/tdutils/td/utils/logging.h b/tdutils/td/utils/logging.h
index dbf4c64b3..bb28f6df8 100644
--- a/tdutils/td/utils/logging.h
+++ b/tdutils/td/utils/logging.h
@@ -264,8 +264,8 @@ class Logger {
     sb_ << other;
     return *this;
   }
-  LambdaPrintHelper<td::Logger> operator<<(const LambdaPrint &) {
-    return LambdaPrintHelper<td::Logger>{*this};
+  LambdaPrintHelper<td::StringBuilder> operator<<(const LambdaPrint &) {
+    return LambdaPrintHelper<td::StringBuilder>{sb_};
   }
 
   MutableCSlice as_cslice() {
diff --git a/ton/ton-types.h b/ton/ton-types.h
index 2447a8c5d..c7aff6448 100644
--- a/ton/ton-types.h
+++ b/ton/ton-types.h
@@ -493,6 +493,7 @@ struct CatChainOptions {
   td::uint64 max_block_height_coeff = 0;
 
   bool debug_disable_db = false;
+  double broadcast_speed_multiplier = 1.0;
 };
 
 struct ValidatorSessionConfig {
diff --git a/validator-engine/validator-engine.cpp b/validator-engine/validator-engine.cpp
index cc7c57b35..2ea04e183 100644
--- a/validator-engine/validator-engine.cpp
+++ b/validator-engine/validator-engine.cpp
@@ -1504,6 +1504,7 @@ td::Status ValidatorEngine::load_global_config() {
   }
   validator_options_.write().set_hardforks(std::move(h));
   validator_options_.write().set_fast_state_serializer_enabled(fast_state_serializer_enabled_);
+  validator_options_.write().set_catchain_broadcast_speed_multiplier(broadcast_speed_multiplier_catchain_);
 
   return td::Status::OK();
 }
@@ -1957,7 +1958,8 @@ void ValidatorEngine::started_overlays() {
 
 void ValidatorEngine::start_validator() {
   validator_options_.write().set_allow_blockchain_init(config_.validators.size() > 0);
-  validator_options_.write().set_state_serializer_enabled(config_.state_serializer_enabled);
+  validator_options_.write().set_state_serializer_enabled(config_.state_serializer_enabled &&
+                                                          !state_serializer_disabled_flag_);
   load_collator_options();
 
   validator_manager_ = ton::validator::ValidatorManagerFactory::create(
@@ -2003,9 +2005,13 @@ void ValidatorEngine::start_full_node() {
       R.ensure();
       td::actor::send_closure(SelfId, &ValidatorEngine::started_full_node);
     });
+    ton::validator::fullnode::FullNodeOptions full_node_options{
+        .config_ = config_.full_node_config,
+        .public_broadcast_speed_multiplier_ = broadcast_speed_multiplier_public_,
+        .private_broadcast_speed_multiplier_ = broadcast_speed_multiplier_private_};
     full_node_ = ton::validator::fullnode::FullNode::create(
         short_id, ton::adnl::AdnlNodeIdShort{config_.full_node}, validator_options_->zero_block_id().file_hash,
-        config_.full_node_config, keyring_.get(), adnl_.get(), rldp_.get(), rldp2_.get(),
+        full_node_options, keyring_.get(), adnl_.get(), rldp_.get(), rldp2_.get(),
         default_dht_node_.is_zero() ? td::actor::ActorId<ton::dht::Dht>{} : dht_nodes_[default_dht_node_].get(),
         overlay_manager_.get(), validator_manager_.get(), full_node_client_.get(), db_root_, std::move(P));
     for (auto &v : config_.validators) {
@@ -3973,7 +3979,7 @@ void ValidatorEngine::run_control_query(ton::ton_api::engine_validator_setStateS
     promise.set_value(ton::create_serialize_tl_object<ton::ton_api::engine_validator_success>());
     return;
   }
-  validator_options_.write().set_state_serializer_enabled(query.enabled_);
+  validator_options_.write().set_state_serializer_enabled(query.enabled_ && !state_serializer_disabled_flag_);
   td::actor::send_closure(validator_manager_, &ton::validator::ValidatorManagerInterface::update_options,
                           validator_options_);
   config_.state_serializer_enabled = query.enabled_;
@@ -4556,6 +4562,47 @@ int main(int argc, char *argv[]) {
               td::actor::send_closure(x, &ValidatorEngine::set_validator_telemetry_filename, s);
             });
       });
+  p.add_option(
+      '\0', "disable-state-serializer",
+      "disable persistent state serializer (similar to set-state-serializer-enabled 0 in validator console)", [&]() {
+        acts.push_back([&x]() { td::actor::send_closure(x, &ValidatorEngine::set_state_serializer_disabled_flag); });
+      });
+  p.add_checked_option(
+      '\0', "broadcast-speed-catchain",
+      "multiplier for broadcast speed in catchain overlays (experimental, default is 1.0, which is ~300 KB/s)",
+      [&](td::Slice s) -> td::Status {
+        auto v = td::to_double(s);
+        if (v <= 0.0) {
+          return td::Status::Error("broadcast-speed-catchain should be positive");
+        }
+        acts.push_back(
+            [&x, v]() { td::actor::send_closure(x, &ValidatorEngine::set_broadcast_speed_multiplier_catchain, v); });
+        return td::Status::OK();
+      });
+  p.add_checked_option(
+      '\0', "broadcast-speed-public",
+      "multiplier for broadcast speed in public shard overlays (experimental, default is 1.0, which is ~300 KB/s)",
+      [&](td::Slice s) -> td::Status {
+        auto v = td::to_double(s);
+        if (v <= 0.0) {
+          return td::Status::Error("broadcast-speed-public should be positive");
+        }
+        acts.push_back(
+            [&x, v]() { td::actor::send_closure(x, &ValidatorEngine::set_broadcast_speed_multiplier_public, v); });
+        return td::Status::OK();
+      });
+  p.add_checked_option(
+      '\0', "broadcast-speed-private",
+      "multiplier for broadcast speed in private block overlays (experimental, default is 1.0, which is ~300 KB/s)",
+      [&](td::Slice s) -> td::Status {
+        auto v = td::to_double(s);
+        if (v <= 0.0) {
+          return td::Status::Error("broadcast-speed-private should be positive");
+        }
+        acts.push_back(
+            [&x, v]() { td::actor::send_closure(x, &ValidatorEngine::set_broadcast_speed_multiplier_private, v); });
+        return td::Status::OK();
+      });
   auto S = p.run(argc, argv);
   if (S.is_error()) {
     LOG(ERROR) << "failed to parse options: " << S.move_as_error();
diff --git a/validator-engine/validator-engine.hpp b/validator-engine/validator-engine.hpp
index b7abb0b1c..e0dc91f13 100644
--- a/validator-engine/validator-engine.hpp
+++ b/validator-engine/validator-engine.hpp
@@ -228,6 +228,10 @@ class ValidatorEngine : public td::actor::Actor {
   std::string validator_telemetry_filename_;
   bool not_all_shards_ = false;
   std::vector<ton::ShardIdFull> add_shard_cmds_;
+  bool state_serializer_disabled_flag_ = false;
+  double broadcast_speed_multiplier_catchain_ = 1.0;
+  double broadcast_speed_multiplier_public_ = 1.0;
+  double broadcast_speed_multiplier_private_ = 1.0;
 
   std::set<ton::CatchainSeqno> unsafe_catchains_;
   std::map<ton::BlockSeqno, std::pair<ton::CatchainSeqno, td::uint32>> unsafe_catchain_rotations_;
@@ -325,6 +329,18 @@ class ValidatorEngine : public td::actor::Actor {
   void add_shard_cmd(ton::ShardIdFull shard) {
     add_shard_cmds_.push_back(shard);
   }
+  void set_state_serializer_disabled_flag() {
+    state_serializer_disabled_flag_ = true;
+  }
+  void set_broadcast_speed_multiplier_catchain(double value) {
+    broadcast_speed_multiplier_catchain_ = value;
+  }
+  void set_broadcast_speed_multiplier_public(double value) {
+    broadcast_speed_multiplier_public_ = value;
+  }
+  void set_broadcast_speed_multiplier_private(double value) {
+    broadcast_speed_multiplier_private_ = value;
+  }
 
   void start_up() override;
   ValidatorEngine() {
diff --git a/validator/db/archive-manager.cpp b/validator/db/archive-manager.cpp
index d349f9d87..8c7cde170 100644
--- a/validator/db/archive-manager.cpp
+++ b/validator/db/archive-manager.cpp
@@ -1196,6 +1196,30 @@ void ArchiveManager::set_async_mode(bool mode, td::Promise<td::Unit> promise) {
   }
 }
 
+void ArchiveManager::prepare_stats(td::Promise<std::vector<std::pair<std::string, std::string>>> promise) {
+  std::vector<std::pair<std::string, std::string>> stats;
+  {
+    std::map<BlockSeqno, td::uint64> states;
+    for (auto &[key, file] : perm_states_) {
+      BlockSeqno seqno = key.first;
+      auto r_stat = td::stat(db_root_ + "/archive/states/" + file.filename_short());
+      if (r_stat.is_error()) {
+        LOG(WARNING) << "Cannot stat persistent state file " << file.filename_short() << " : " << r_stat.move_as_error();
+      } else {
+        states[seqno] += r_stat.move_as_ok().size_;
+      }
+    }
+    td::StringBuilder sb;
+    for (auto &[seqno, size] : states) {
+      sb << seqno << ":" << td::format::as_size(size) << " ";
+    }
+    if (!sb.as_cslice().empty()) {
+      stats.emplace_back("persistent_states", sb.as_cslice().str());
+    }
+  }
+  promise.set_value(std::move(stats));
+}
+
 void ArchiveManager::truncate(BlockSeqno masterchain_seqno, ConstBlockHandle handle, td::Promise<td::Unit> promise) {
   index_->begin_transaction().ensure();
   td::MultiPromise mp;
diff --git a/validator/db/archive-manager.hpp b/validator/db/archive-manager.hpp
index 90fc6a0b0..d919e32ee 100644
--- a/validator/db/archive-manager.hpp
+++ b/validator/db/archive-manager.hpp
@@ -81,6 +81,8 @@ class ArchiveManager : public td::actor::Actor {
     cur_shard_split_depth_ = value;
   }
 
+  void prepare_stats(td::Promise<std::vector<std::pair<std::string, std::string>>> promise);
+
   static constexpr td::uint32 archive_size() {
     return 20000;
   }
diff --git a/validator/db/celldb.cpp b/validator/db/celldb.cpp
index 9dcecdb35..e86a373d1 100644
--- a/validator/db/celldb.cpp
+++ b/validator/db/celldb.cpp
@@ -158,6 +158,17 @@ void CellDbIn::start_up() {
         },
         td::Timestamp::now());
   }
+
+  {
+    std::string key = "stats.last_deleted_mc_seqno", value;
+    auto R = cell_db_->get(td::as_slice(key), value);
+    R.ensure();
+    if (R.ok() == td::KeyValue::GetStatus::Ok) {
+      auto r_value = td::to_integer_safe<BlockSeqno>(value);
+      r_value.ensure();
+      last_deleted_mc_state_ = r_value.move_as_ok();
+    }
+  }
 }
 
 void CellDbIn::load_cell(RootHash hash, td::Promise<td::Ref<vm::DataCell>> promise) {
@@ -452,6 +463,11 @@ void CellDbIn::gc_cont2(BlockHandle handle) {
           cell_db_->erase(get_key(key_hash)).ensure();
           set_block(F.prev, std::move(P));
           set_block(F.next, std::move(N));
+          if (handle->id().is_masterchain()) {
+            last_deleted_mc_state_ = handle->id().seqno();
+            std::string key = "stats.last_deleted_mc_seqno", value = td::to_string(last_deleted_mc_state_);
+            cell_db_->set(td::as_slice(key), td::as_slice(value));
+          }
           cell_db_->commit_write_batch().ensure();
           alarm_timestamp() = td::Timestamp::now();
           timer_write_batch.reset();
@@ -475,9 +491,6 @@ void CellDbIn::gc_cont2(BlockHandle handle) {
           if (!opts_->get_disable_rocksdb_stats()) {
             cell_db_statistics_.gc_cell_time_.insert(timer.elapsed() * 1e6);
           }
-          if (handle->id().is_masterchain()) {
-            last_deleted_mc_state_ = handle->id().seqno();
-          }
           LOG(DEBUG) << "Deleted state " << handle->id().to_str();
           timer_finish.reset();
           timer_all.reset();
diff --git a/validator/db/rootdb.cpp b/validator/db/rootdb.cpp
index e0579d570..8d83e7a7d 100644
--- a/validator/db/rootdb.cpp
+++ b/validator/db/rootdb.cpp
@@ -438,6 +438,7 @@ void RootDb::allow_block_gc(BlockIdExt block_id, td::Promise<bool> promise) {
 void RootDb::prepare_stats(td::Promise<std::vector<std::pair<std::string, std::string>>> promise) {
   auto merger = StatsMerger::create(std::move(promise));
   td::actor::send_closure(cell_db_, &CellDb::prepare_stats, merger.make_promise("celldb."));
+  td::actor::send_closure(archive_db_, &ArchiveManager::prepare_stats, merger.make_promise("archive."));
 }
 
 void RootDb::truncate(BlockSeqno seqno, ConstBlockHandle handle, td::Promise<td::Unit> promise) {
diff --git a/validator/downloaders/download-state.cpp b/validator/downloaders/download-state.cpp
index 32978ea5b..8473cb228 100644
--- a/validator/downloaders/download-state.cpp
+++ b/validator/downloaders/download-state.cpp
@@ -38,6 +38,7 @@ DownloadShardState::DownloadShardState(BlockIdExt block_id, BlockIdExt mastercha
 }
 
 void DownloadShardState::start_up() {
+  status_ = ProcessStatus(manager_, "process.download_state");
   alarm_timestamp() = timeout_;
 
   auto P = td::PromiseCreator::lambda([SelfId = actor_id(this)](td::Result<BlockHandle> R) {
@@ -81,6 +82,7 @@ void DownloadShardState::download_state() {
   });
   td::actor::send_closure(manager_, &ValidatorManager::send_get_block_proof_link_request, block_id_, priority_,
                           std::move(P));
+  status_.set_status(PSTRING() << block_id_.id.to_str() << " : downloading proof");
 }
 
 void DownloadShardState::downloaded_proof_link(td::BufferSlice data) {
@@ -123,6 +125,7 @@ void DownloadShardState::checked_proof_link() {
     td::actor::send_closure(manager_, &ValidatorManager::send_get_persistent_state_request, block_id_,
                             masterchain_block_id_, priority_, std::move(P));
   }
+  status_.set_status(PSTRING() << block_id_.id.to_str() << " : downloading state");
 }
 
 void DownloadShardState::download_zero_state() {
@@ -152,6 +155,7 @@ void DownloadShardState::downloaded_zero_state(td::BufferSlice data) {
 }
 
 void DownloadShardState::downloaded_shard_state(td::BufferSlice data) {
+  status_.set_status(PSTRING() << block_id_.id.to_str() << " : processing downloaded state");
   auto S = create_shard_state(block_id_, data.clone());
   if (S.is_error()) {
     fail_handler(actor_id(this), S.move_as_error());
@@ -174,6 +178,7 @@ void DownloadShardState::downloaded_shard_state(td::BufferSlice data) {
 }
 
 void DownloadShardState::checked_shard_state() {
+  status_.set_status(PSTRING() << block_id_.id.to_str() << " : storing state file");
   LOG(WARNING) << "checked shard state " << block_id_.to_str();
   auto P = td::PromiseCreator::lambda([SelfId = actor_id(this)](td::Result<td::Unit> R) {
     R.ensure();
@@ -189,6 +194,7 @@ void DownloadShardState::checked_shard_state() {
 }
 
 void DownloadShardState::written_shard_state_file() {
+  status_.set_status(PSTRING() << block_id_.id.to_str() << " : storing state to celldb");
   LOG(WARNING) << "written shard state file " << block_id_.to_str();
   auto P = td::PromiseCreator::lambda([SelfId = actor_id(this)](td::Result<td::Ref<ShardState>> R) {
     R.ensure();
@@ -198,6 +204,7 @@ void DownloadShardState::written_shard_state_file() {
 }
 
 void DownloadShardState::written_shard_state(td::Ref<ShardState> state) {
+  status_.set_status(PSTRING() << block_id_.id.to_str() << " : finishing");
   state_ = std::move(state);
   handle_->set_unix_time(state_->get_unix_time());
   handle_->set_is_key_block(block_id_.is_masterchain());
diff --git a/validator/downloaders/download-state.hpp b/validator/downloaders/download-state.hpp
index 02984c53c..bde80aae1 100644
--- a/validator/downloaders/download-state.hpp
+++ b/validator/downloaders/download-state.hpp
@@ -19,6 +19,7 @@
 #pragma once
 
 #include "validator/interfaces/validator-manager.h"
+#include "stats-provider.h"
 
 namespace ton {
 
@@ -67,6 +68,8 @@ class DownloadShardState : public td::actor::Actor {
 
   td::BufferSlice data_;
   td::Ref<ShardState> state_;
+
+  ProcessStatus status_;
 };
 
 }  // namespace validator
diff --git a/validator/full-node-private-overlay.cpp b/validator/full-node-private-overlay.cpp
index 1acfbd4ed..f86323fc0 100644
--- a/validator/full-node-private-overlay.cpp
+++ b/validator/full-node-private-overlay.cpp
@@ -264,8 +264,11 @@ void FullNodePrivateBlockOverlay::init() {
   overlay::OverlayPrivacyRules rules{overlay::Overlays::max_fec_broadcast_size(),
                                      overlay::CertificateFlags::AllowFec | overlay::CertificateFlags::Trusted,
                                      {}};
-  td::actor::send_closure(overlays_, &overlay::Overlays::create_private_overlay, local_id_, overlay_id_full_.clone(),
-                          nodes_, std::make_unique<Callback>(actor_id(this)), rules, R"({ "type": "private-blocks" })");
+  overlay::OverlayOptions overlay_options;
+  overlay_options.broadcast_speed_multiplier_ = opts_.private_broadcast_speed_multiplier_;
+  td::actor::send_closure(overlays_, &overlay::Overlays::create_private_overlay_ex, local_id_, overlay_id_full_.clone(),
+                          nodes_, std::make_unique<Callback>(actor_id(this)), rules, R"({ "type": "private-blocks" })",
+                          overlay_options);
 
   td::actor::send_closure(rldp_, &rldp::Rldp::add_id, local_id_);
   td::actor::send_closure(rldp2_, &rldp2::Rldp::add_id, local_id_);
@@ -366,7 +369,7 @@ void FullNodeCustomOverlay::receive_broadcast(PublicKeyHash src, td::BufferSlice
 }
 
 void FullNodeCustomOverlay::send_external_message(td::BufferSlice data) {
-  if (!inited_ || config_.ext_messages_broadcast_disabled_) {
+  if (!inited_ || opts_.config_.ext_messages_broadcast_disabled_) {
     return;
   }
   VLOG(FULL_NODE_DEBUG) << "Sending external message to custom overlay \"" << name_ << "\"";
@@ -472,10 +475,13 @@ void FullNodeCustomOverlay::init() {
     authorized_keys[sender.pubkey_hash()] = overlay::Overlays::max_fec_broadcast_size();
   }
   overlay::OverlayPrivacyRules rules{overlay::Overlays::max_fec_broadcast_size(), 0, std::move(authorized_keys)};
+  overlay::OverlayOptions overlay_options;
+  overlay_options.broadcast_speed_multiplier_ = opts_.private_broadcast_speed_multiplier_;
   td::actor::send_closure(
-      overlays_, &overlay::Overlays::create_private_overlay, local_id_, overlay_id_full_.clone(), nodes_,
+      overlays_, &overlay::Overlays::create_private_overlay_ex, local_id_, overlay_id_full_.clone(), nodes_,
       std::make_unique<Callback>(actor_id(this)), rules,
-      PSTRING() << R"({ "type": "custom-overlay", "name": ")" << td::format::Escaped{name_} << R"(" })");
+      PSTRING() << R"({ "type": "custom-overlay", "name": ")" << td::format::Escaped{name_} << R"(" })",
+      overlay_options);
 
   td::actor::send_closure(rldp_, &rldp::Rldp::add_id, local_id_);
   td::actor::send_closure(rldp2_, &rldp2::Rldp::add_id, local_id_);
diff --git a/validator/full-node-private-overlay.hpp b/validator/full-node-private-overlay.hpp
index 1e29f8c93..70e196ea6 100644
--- a/validator/full-node-private-overlay.hpp
+++ b/validator/full-node-private-overlay.hpp
@@ -50,14 +50,14 @@ class FullNodePrivateBlockOverlay : public td::actor::Actor {
   void collect_validator_telemetry(std::string filename);
 
   void set_config(FullNodeConfig config) {
-    config_ = std::move(config);
+    opts_.config_ = std::move(config);
   }
 
   void start_up() override;
   void tear_down() override;
 
   FullNodePrivateBlockOverlay(adnl::AdnlNodeIdShort local_id, std::vector<adnl::AdnlNodeIdShort> nodes,
-                              FileHash zero_state_file_hash, FullNodeConfig config,
+                              FileHash zero_state_file_hash, FullNodeOptions opts,
                               td::actor::ActorId<keyring::Keyring> keyring, td::actor::ActorId<adnl::Adnl> adnl,
                               td::actor::ActorId<rldp::Rldp> rldp, td::actor::ActorId<rldp2::Rldp> rldp2,
                               td::actor::ActorId<overlay::Overlays> overlays,
@@ -66,7 +66,7 @@ class FullNodePrivateBlockOverlay : public td::actor::Actor {
       : local_id_(local_id)
       , nodes_(std::move(nodes))
       , zero_state_file_hash_(zero_state_file_hash)
-      , config_(config)
+      , opts_(opts)
       , keyring_(keyring)
       , adnl_(adnl)
       , rldp_(rldp)
@@ -80,7 +80,7 @@ class FullNodePrivateBlockOverlay : public td::actor::Actor {
   adnl::AdnlNodeIdShort local_id_;
   std::vector<adnl::AdnlNodeIdShort> nodes_;
   FileHash zero_state_file_hash_;
-  FullNodeConfig config_;
+  FullNodeOptions opts_;
   bool enable_compression_ = true;
 
   td::actor::ActorId<keyring::Keyring> keyring_;
@@ -126,14 +126,14 @@ class FullNodeCustomOverlay : public td::actor::Actor {
                             td::BufferSlice data);
 
   void set_config(FullNodeConfig config) {
-    config_ = std::move(config);
+    opts_.config_ = std::move(config);
   }
 
   void start_up() override;
   void tear_down() override;
 
   FullNodeCustomOverlay(adnl::AdnlNodeIdShort local_id, CustomOverlayParams params, FileHash zero_state_file_hash,
-                        FullNodeConfig config, td::actor::ActorId<keyring::Keyring> keyring,
+                        FullNodeOptions opts, td::actor::ActorId<keyring::Keyring> keyring,
                         td::actor::ActorId<adnl::Adnl> adnl, td::actor::ActorId<rldp::Rldp> rldp,
                         td::actor::ActorId<rldp2::Rldp> rldp2, td::actor::ActorId<overlay::Overlays> overlays,
                         td::actor::ActorId<ValidatorManagerInterface> validator_manager,
@@ -144,7 +144,7 @@ class FullNodeCustomOverlay : public td::actor::Actor {
       , msg_senders_(std::move(params.msg_senders_))
       , block_senders_(std::move(params.block_senders_))
       , zero_state_file_hash_(zero_state_file_hash)
-      , config_(config)
+      , opts_(opts)
       , keyring_(keyring)
       , adnl_(adnl)
       , rldp_(rldp)
@@ -161,7 +161,7 @@ class FullNodeCustomOverlay : public td::actor::Actor {
   std::map<adnl::AdnlNodeIdShort, int> msg_senders_;
   std::set<adnl::AdnlNodeIdShort> block_senders_;
   FileHash zero_state_file_hash_;
-  FullNodeConfig config_;
+  FullNodeOptions opts_;
 
   td::actor::ActorId<keyring::Keyring> keyring_;
   td::actor::ActorId<adnl::Adnl> adnl_;
diff --git a/validator/full-node-shard.cpp b/validator/full-node-shard.cpp
index 7d33a1950..ac0eb7688 100644
--- a/validator/full-node-shard.cpp
+++ b/validator/full-node-shard.cpp
@@ -105,6 +105,7 @@ void FullNodeShardImpl::create_overlay() {
   };
   overlay::OverlayOptions opts;
   opts.announce_self_ = active_;
+  opts.broadcast_speed_multiplier_ = opts_.public_broadcast_speed_multiplier_;
   td::actor::send_closure(overlays_, &overlay::Overlays::create_public_overlay_ex, adnl_id_, overlay_id_full_.clone(),
                           std::make_unique<Callback>(actor_id(this)), rules_,
                           PSTRING() << "{ \"type\": \"shard\", \"shard_id\": " << get_shard()
@@ -132,7 +133,7 @@ void FullNodeShardImpl::check_broadcast(PublicKeyHash src, td::BufferSlice broad
   if (!processed_ext_msg_broadcasts_.insert(hash).second) {
     return promise.set_error(td::Status::Error("duplicate external message broadcast"));
   }
-  if (config_.ext_messages_broadcast_disabled_) {
+  if (opts_.config_.ext_messages_broadcast_disabled_) {
     promise.set_error(td::Status::Error("rebroadcasting external messages is disabled"));
     promise = [manager = validator_manager_, message = q->message_->data_.clone()](td::Result<td::Unit> R) mutable {
       if (R.is_ok()) {
@@ -850,7 +851,7 @@ void FullNodeShardImpl::send_ihr_message(td::BufferSlice data) {
 }
 
 void FullNodeShardImpl::send_external_message(td::BufferSlice data) {
-  if (config_.ext_messages_broadcast_disabled_) {
+  if (opts_.config_.ext_messages_broadcast_disabled_) {
     return;
   }
   if (!client_.empty()) {
@@ -1367,7 +1368,7 @@ void FullNodeShardImpl::get_stats_extra(td::Promise<std::string> promise) {
 }
 
 FullNodeShardImpl::FullNodeShardImpl(ShardIdFull shard, PublicKeyHash local_id, adnl::AdnlNodeIdShort adnl_id,
-                                     FileHash zero_state_file_hash, FullNodeConfig config,
+                                     FileHash zero_state_file_hash, FullNodeOptions opts,
                                      td::actor::ActorId<keyring::Keyring> keyring, td::actor::ActorId<adnl::Adnl> adnl,
                                      td::actor::ActorId<rldp::Rldp> rldp, td::actor::ActorId<rldp2::Rldp> rldp2,
                                      td::actor::ActorId<overlay::Overlays> overlays,
@@ -1387,17 +1388,17 @@ FullNodeShardImpl::FullNodeShardImpl(ShardIdFull shard, PublicKeyHash local_id,
     , client_(client)
     , full_node_(full_node)
     , active_(active)
-    , config_(config) {
+    , opts_(opts) {
 }
 
 td::actor::ActorOwn<FullNodeShard> FullNodeShard::create(
     ShardIdFull shard, PublicKeyHash local_id, adnl::AdnlNodeIdShort adnl_id, FileHash zero_state_file_hash,
-    FullNodeConfig config, td::actor::ActorId<keyring::Keyring> keyring, td::actor::ActorId<adnl::Adnl> adnl,
+    FullNodeOptions opts, td::actor::ActorId<keyring::Keyring> keyring, td::actor::ActorId<adnl::Adnl> adnl,
     td::actor::ActorId<rldp::Rldp> rldp, td::actor::ActorId<rldp2::Rldp> rldp2,
     td::actor::ActorId<overlay::Overlays> overlays, td::actor::ActorId<ValidatorManagerInterface> validator_manager,
     td::actor::ActorId<adnl::AdnlExtClient> client, td::actor::ActorId<FullNode> full_node, bool active) {
   return td::actor::create_actor<FullNodeShardImpl>(PSTRING() << "tonnode" << shard.to_str(), shard, local_id, adnl_id,
-                                                    zero_state_file_hash, config, keyring, adnl, rldp, rldp2, overlays,
+                                                    zero_state_file_hash, opts, keyring, adnl, rldp, rldp2, overlays,
                                                     validator_manager, client, full_node, active);
 }
 
diff --git a/validator/full-node-shard.h b/validator/full-node-shard.h
index 169453257..5898db80d 100644
--- a/validator/full-node-shard.h
+++ b/validator/full-node-shard.h
@@ -76,7 +76,7 @@ class FullNodeShard : public td::actor::Actor {
 
   static td::actor::ActorOwn<FullNodeShard> create(
       ShardIdFull shard, PublicKeyHash local_id, adnl::AdnlNodeIdShort adnl_id, FileHash zero_state_file_hash,
-      FullNodeConfig config, td::actor::ActorId<keyring::Keyring> keyring, td::actor::ActorId<adnl::Adnl> adnl,
+      FullNodeOptions opts, td::actor::ActorId<keyring::Keyring> keyring, td::actor::ActorId<adnl::Adnl> adnl,
       td::actor::ActorId<rldp::Rldp> rldp, td::actor::ActorId<rldp2::Rldp> rldp2,
       td::actor::ActorId<overlay::Overlays> overlays, td::actor::ActorId<ValidatorManagerInterface> validator_manager,
       td::actor::ActorId<adnl::AdnlExtClient> client, td::actor::ActorId<FullNode> full_node, bool active);
diff --git a/validator/full-node-shard.hpp b/validator/full-node-shard.hpp
index 867481346..fb3eef769 100644
--- a/validator/full-node-shard.hpp
+++ b/validator/full-node-shard.hpp
@@ -86,7 +86,7 @@ class FullNodeShardImpl : public FullNodeShard {
   void set_active(bool active) override;
 
   void set_config(FullNodeConfig config) override {
-    config_ = config;
+    opts_.config_ = config;
   }
 
   void try_get_next_block(td::Timestamp timestamp, td::Promise<ReceivedBlock> promise);
@@ -222,7 +222,7 @@ class FullNodeShardImpl : public FullNodeShard {
   }
 
   FullNodeShardImpl(ShardIdFull shard, PublicKeyHash local_id, adnl::AdnlNodeIdShort adnl_id,
-                    FileHash zero_state_file_hash, FullNodeConfig config, td::actor::ActorId<keyring::Keyring> keyring,
+                    FileHash zero_state_file_hash, FullNodeOptions opts, td::actor::ActorId<keyring::Keyring> keyring,
                     td::actor::ActorId<adnl::Adnl> adnl, td::actor::ActorId<rldp::Rldp> rldp,
                     td::actor::ActorId<rldp2::Rldp> rldp2, td::actor::ActorId<overlay::Overlays> overlays,
                     td::actor::ActorId<ValidatorManagerInterface> validator_manager,
@@ -269,7 +269,7 @@ class FullNodeShardImpl : public FullNodeShard {
 
   bool active_;
 
-  FullNodeConfig config_;
+  FullNodeOptions opts_;
 
   std::set<td::Bits256> my_ext_msg_broadcasts_;
   std::set<td::Bits256> processed_ext_msg_broadcasts_;
diff --git a/validator/full-node.cpp b/validator/full-node.cpp
index 658cb34e3..e1951c365 100644
--- a/validator/full-node.cpp
+++ b/validator/full-node.cpp
@@ -139,7 +139,7 @@ void FullNodeImpl::update_adnl_id(adnl::AdnlNodeIdShort adnl_id, td::Promise<td:
 }
 
 void FullNodeImpl::set_config(FullNodeConfig config) {
-  config_ = config;
+  opts_.config_ = config;
   for (auto& s : shards_) {
     if (!s.second.actor.empty()) {
       td::actor::send_closure(s.second.actor, &FullNodeShard::set_config, config);
@@ -256,7 +256,7 @@ void FullNodeImpl::on_new_masterchain_block(td::Ref<MasterchainState> state, std
 void FullNodeImpl::update_shard_actor(ShardIdFull shard, bool active) {
   ShardInfo &info = shards_[shard];
   if (info.actor.empty()) {
-    info.actor = FullNodeShard::create(shard, local_id_, adnl_id_, zero_state_file_hash_, config_, keyring_, adnl_, rldp_,
+    info.actor = FullNodeShard::create(shard, local_id_, adnl_id_, zero_state_file_hash_, opts_, keyring_, adnl_, rldp_,
                                        rldp2_, overlays_, validator_manager_, client_, actor_id(this), active);
     if (!all_validators_.empty()) {
       td::actor::send_closure(info.actor, &FullNodeShard::update_validators, all_validators_, sign_cert_by_);
@@ -717,7 +717,7 @@ void FullNodeImpl::create_private_block_overlay(PublicKeyHash key) {
       nodes.push_back(p.second);
     }
     private_block_overlays_[key] = td::actor::create_actor<FullNodePrivateBlockOverlay>(
-        "BlocksPrivateOverlay", current_validators_[key], std::move(nodes), zero_state_file_hash_, config_, keyring_,
+        "BlocksPrivateOverlay", current_validators_[key], std::move(nodes), zero_state_file_hash_, opts_, keyring_,
         adnl_, rldp_, rldp2_, overlays_, validator_manager_, actor_id(this));
     update_validator_telemetry_collector();
   }
@@ -735,7 +735,7 @@ void FullNodeImpl::update_custom_overlay(CustomOverlayInfo &overlay) {
         old_actors.erase(it);
       } else {
         overlay.actors_[local_id] = td::actor::create_actor<FullNodeCustomOverlay>(
-            "CustomOverlay", local_id, params, zero_state_file_hash_, config_, keyring_, adnl_, rldp_, rldp2_,
+            "CustomOverlay", local_id, params, zero_state_file_hash_, opts_, keyring_, adnl_, rldp_, rldp2_,
             overlays_, validator_manager_, actor_id(this));
       }
     }
@@ -794,7 +794,7 @@ void FullNodeImpl::send_block_candidate_broadcast_to_custom_overlays(const Block
 }
 
 FullNodeImpl::FullNodeImpl(PublicKeyHash local_id, adnl::AdnlNodeIdShort adnl_id, FileHash zero_state_file_hash,
-                           FullNodeConfig config, td::actor::ActorId<keyring::Keyring> keyring,
+                           FullNodeOptions opts, td::actor::ActorId<keyring::Keyring> keyring,
                            td::actor::ActorId<adnl::Adnl> adnl, td::actor::ActorId<rldp::Rldp> rldp,
                            td::actor::ActorId<rldp2::Rldp> rldp2, td::actor::ActorId<dht::Dht> dht,
                            td::actor::ActorId<overlay::Overlays> overlays,
@@ -814,16 +814,16 @@ FullNodeImpl::FullNodeImpl(PublicKeyHash local_id, adnl::AdnlNodeIdShort adnl_id
     , client_(client)
     , db_root_(db_root)
     , started_promise_(std::move(started_promise))
-    , config_(config) {
+    , opts_(opts) {
 }
 
 td::actor::ActorOwn<FullNode> FullNode::create(
-    ton::PublicKeyHash local_id, adnl::AdnlNodeIdShort adnl_id, FileHash zero_state_file_hash, FullNodeConfig config,
+    ton::PublicKeyHash local_id, adnl::AdnlNodeIdShort adnl_id, FileHash zero_state_file_hash, FullNodeOptions opts,
     td::actor::ActorId<keyring::Keyring> keyring, td::actor::ActorId<adnl::Adnl> adnl,
     td::actor::ActorId<rldp::Rldp> rldp, td::actor::ActorId<rldp2::Rldp> rldp2, td::actor::ActorId<dht::Dht> dht,
     td::actor::ActorId<overlay::Overlays> overlays, td::actor::ActorId<ValidatorManagerInterface> validator_manager,
     td::actor::ActorId<adnl::AdnlExtClient> client, std::string db_root, td::Promise<td::Unit> started_promise) {
-  return td::actor::create_actor<FullNodeImpl>("fullnode", local_id, adnl_id, zero_state_file_hash, config, keyring,
+  return td::actor::create_actor<FullNodeImpl>("fullnode", local_id, adnl_id, zero_state_file_hash, opts, keyring,
                                                adnl, rldp, rldp2, dht, overlays, validator_manager, client, db_root,
                                                std::move(started_promise));
 }
diff --git a/validator/full-node.h b/validator/full-node.h
index fdb1bf3b0..555082dc5 100644
--- a/validator/full-node.h
+++ b/validator/full-node.h
@@ -55,6 +55,12 @@ struct FullNodeConfig {
   bool ext_messages_broadcast_disabled_ = false;
 };
 
+struct FullNodeOptions {
+  FullNodeConfig config_;
+  double public_broadcast_speed_multiplier_ = 1.0;
+  double private_broadcast_speed_multiplier_ = 1.0;
+};
+
 struct CustomOverlayParams {
   std::string name_;
   std::vector<adnl::AdnlNodeIdShort> nodes_;
@@ -107,7 +113,7 @@ class FullNode : public td::actor::Actor {
   enum { broadcast_mode_public = 1, broadcast_mode_private_block = 2, broadcast_mode_custom = 4 };
 
   static td::actor::ActorOwn<FullNode> create(
-      ton::PublicKeyHash local_id, adnl::AdnlNodeIdShort adnl_id, FileHash zero_state_file_hash, FullNodeConfig config,
+      ton::PublicKeyHash local_id, adnl::AdnlNodeIdShort adnl_id, FileHash zero_state_file_hash, FullNodeOptions opts,
       td::actor::ActorId<keyring::Keyring> keyring, td::actor::ActorId<adnl::Adnl> adnl,
       td::actor::ActorId<rldp::Rldp> rldp, td::actor::ActorId<rldp2::Rldp> rldp2, td::actor::ActorId<dht::Dht> dht,
       td::actor::ActorId<overlay::Overlays> overlays, td::actor::ActorId<ValidatorManagerInterface> validator_manager,
diff --git a/validator/full-node.hpp b/validator/full-node.hpp
index 0ea6fa0b3..b4c79363e 100644
--- a/validator/full-node.hpp
+++ b/validator/full-node.hpp
@@ -98,7 +98,7 @@ class FullNodeImpl : public FullNode {
   void start_up() override;
 
   FullNodeImpl(PublicKeyHash local_id, adnl::AdnlNodeIdShort adnl_id, FileHash zero_state_file_hash,
-               FullNodeConfig config, td::actor::ActorId<keyring::Keyring> keyring, td::actor::ActorId<adnl::Adnl> adnl,
+               FullNodeOptions opts, td::actor::ActorId<keyring::Keyring> keyring, td::actor::ActorId<adnl::Adnl> adnl,
                td::actor::ActorId<rldp::Rldp> rldp, td::actor::ActorId<rldp2::Rldp> rldp2,
                td::actor::ActorId<dht::Dht> dht, td::actor::ActorId<overlay::Overlays> overlays,
                td::actor::ActorId<ValidatorManagerInterface> validator_manager,
@@ -141,7 +141,7 @@ class FullNodeImpl : public FullNode {
   std::set<PublicKeyHash> local_keys_;
 
   td::Promise<td::Unit> started_promise_;
-  FullNodeConfig config_;
+  FullNodeOptions opts_;
 
   std::map<PublicKeyHash, td::actor::ActorOwn<FullNodePrivateBlockOverlay>> private_block_overlays_;
   bool broadcast_block_candidates_in_public_overlay_ = false;
diff --git a/validator/impl/accept-block.cpp b/validator/impl/accept-block.cpp
index a9dd7fe27..de48626d7 100644
--- a/validator/impl/accept-block.cpp
+++ b/validator/impl/accept-block.cpp
@@ -308,8 +308,11 @@ bool AcceptBlockQuery::create_new_proof() {
   }
   // 10. check resulting object
   if (!block::gen::t_BlockProof.validate_ref(bs_cell)) {
-    block::gen::t_BlockProof.print_ref(std::cerr, bs_cell);
-    vm::load_cell_slice(bs_cell).print_rec(std::cerr);
+    FLOG(WARNING) {
+      sb << "BlockProof object just created failed to pass automated consistency checks: ";
+      block::gen::t_BlockProof.print_ref(sb, bs_cell);
+      vm::load_cell_slice(bs_cell).print_rec(sb);
+    };
     return fatal_error("BlockProof object just created failed to pass automated consistency checks");
   }
   // 11. create a proof object from this cell
@@ -851,15 +854,12 @@ bool AcceptBlockQuery::create_top_shard_block_description() {
         && (root.is_null() || cb.store_ref_bool(std::move(root))) && cb.finalize_to(td_cell))) {
     return fatal_error("cannot serialize ShardTopBlockDescription for the newly-accepted block "s + id_.to_str());
   }
-  if (false) {
-    // debug output
-    std::cerr << "new ShardTopBlockDescription: ";
-    block::gen::t_TopBlockDescr.print_ref(std::cerr, td_cell);
-    vm::load_cell_slice(td_cell).print_rec(std::cerr);
-  }
   if (!block::gen::t_TopBlockDescr.validate_ref(td_cell)) {
-    block::gen::t_TopBlockDescr.print_ref(std::cerr, td_cell);
-    vm::load_cell_slice(td_cell).print_rec(std::cerr);
+    FLOG(WARNING) {
+      sb << "just created ShardTopBlockDescription is invalid: ";
+      block::gen::t_TopBlockDescr.print_ref(sb, td_cell);
+      vm::load_cell_slice(td_cell).print_rec(sb);
+    };
     return fatal_error("just created ShardTopBlockDescription for "s + id_.to_str() + " is invalid");
   }
   auto res = vm::std_boc_serialize(td_cell, 0);
diff --git a/validator/impl/collator-impl.h b/validator/impl/collator-impl.h
index a781968db..ce21bc5e1 100644
--- a/validator/impl/collator-impl.h
+++ b/validator/impl/collator-impl.h
@@ -50,7 +50,7 @@ class Collator final : public td::actor::Actor {
   using LtCellRef = block::LtCellRef;
   using NewOutMsg = block::NewOutMsg;
   const ShardIdFull shard_;
-  ton::BlockId new_id;
+  ton::BlockId new_id{workchainInvalid, 0, 0};
   bool busy_{false};
   bool before_split_{false};
   bool after_split_{false};
diff --git a/validator/impl/collator.cpp b/validator/impl/collator.cpp
index e171eaa12..d5c418537 100644
--- a/validator/impl/collator.cpp
+++ b/validator/impl/collator.cpp
@@ -53,16 +53,6 @@ static constexpr int HIGH_PRIORITY_EXTERNAL = 10;  // don't skip high priority e
 
 static constexpr int MAX_ATTEMPTS = 5;
 
-#define DBG(__n) dbg(__n)&&
-#define DSTART int __dcnt = 0;
-#define DEB DBG(++__dcnt)
-
-static inline bool dbg(int c) TD_UNUSED;
-static inline bool dbg(int c) {
-  std::cerr << '[' << (char)('0' + c / 10) << (char)('0' + c % 10) << ']';
-  return true;
-}
-
 /**
  * Constructs a Collator object.
  *
@@ -362,6 +352,8 @@ bool Collator::fatal_error(td::Status error) {
                         attempt_idx_ + 1);
     } else {
       main_promise(std::move(error));
+      td::actor::send_closure(manager, &ValidatorManager::record_collate_query_stats, BlockIdExt{new_id, RootHash::zero(), FileHash::zero()},
+                              work_timer_.elapsed(), cpu_work_timer_.elapsed(), td::optional<CollationStats>{});
     }
     busy_ = false;
   }
@@ -761,8 +753,6 @@ bool Collator::unpack_last_mc_state() {
                << " (upgrade validator software?)";
   }
   // TODO: extract start_lt and end_lt from prev_mc_block as well
-  // std::cerr << "  block::gen::ShardState::print_ref(mc_state_root) = ";
-  // block::gen::t_ShardState.print_ref(std::cerr, mc_state_root, 2);
   return true;
 }
 
@@ -888,8 +878,10 @@ void Collator::got_neighbor_out_queue(int i, td::Result<Ref<MessageQueue>> res)
   // unpack ProcessedUpto
   LOG(DEBUG) << "unpacking ProcessedUpto of neighbor " << descr.blk_.to_str();
   if (verbosity >= 2) {
-    block::gen::t_ProcessedInfo.print(std::cerr, qinfo.proc_info);
-    qinfo.proc_info->print_rec(std::cerr);
+    FLOG(INFO) {
+      block::gen::t_ProcessedInfo.print(sb, qinfo.proc_info);
+      qinfo.proc_info->print_rec(sb);
+    };
   }
   descr.processed_upto = block::MsgProcessedUptoCollection::unpack(descr.shard(), qinfo.proc_info);
   if (!descr.processed_upto) {
@@ -1756,9 +1748,11 @@ bool Collator::import_new_shard_top_blocks() {
     shard_conf_adjusted_ = true;
   }
   if (tb_act && verbosity >= 0) {  // DEBUG
-    LOG(INFO) << "updated shard block configuration to ";
-    auto csr = shard_conf_->get_root_csr();
-    block::gen::t_ShardHashes.print(std::cerr, csr.write());
+    FLOG(INFO) {
+      sb << "updated shard block configuration to ";
+      auto csr = shard_conf_->get_root_csr();
+      block::gen::t_ShardHashes.print(sb, csr);
+    };
   }
   block::gen::ShardFeeCreated::Record fc;
   if (!(tlb::csr_unpack(fees_import_dict_->get_root_extra(),
@@ -2279,10 +2273,12 @@ bool Collator::dequeue_message(Ref<vm::Cell> msg_envelope, ton::LogicalTime deli
 bool Collator::out_msg_queue_cleanup() {
   LOG(INFO) << "cleaning outbound queue from messages already imported by neighbors";
   if (verbosity >= 2) {
-    auto rt = out_msg_queue_->get_root();
-    std::cerr << "old out_msg_queue is ";
-    block::gen::t_OutMsgQueue.print(std::cerr, *rt);
-    rt->print_rec(std::cerr);
+    FLOG(INFO) {
+      auto rt = out_msg_queue_->get_root();
+      sb << "old out_msg_queue is ";
+      block::gen::t_OutMsgQueue.print(sb, rt);
+      rt->print_rec(sb);
+    };
   }
 
   if (after_merge_) {
@@ -2422,10 +2418,12 @@ bool Collator::out_msg_queue_cleanup() {
                  << out_msg_queue_size_;
   }
   if (verbosity >= 2) {
-    auto rt = out_msg_queue_->get_root();
-    std::cerr << "new out_msg_queue is ";
-    block::gen::t_OutMsgQueue.print(std::cerr, *rt);
-    rt->print_rec(std::cerr);
+    FLOG(INFO) {
+      auto rt = out_msg_queue_->get_root();
+      sb << "new out_msg_queue is ";
+      block::gen::t_OutMsgQueue.print(sb, rt);
+      rt->print_rec(sb);
+    };
   }
   return register_out_msg_queue_op(true);
 }
@@ -2524,19 +2522,27 @@ bool Collator::combine_account_transactions() {
       auto cell = cb.finalize();
       auto csr = vm::load_cell_slice_ref(cell);
       if (verbosity > 2) {
-        std::cerr << "new AccountBlock for " << z.first.to_hex() << ": ";
-        block::gen::t_AccountBlock.print_ref(std::cerr, cell);
-        csr->print_rec(std::cerr);
+        FLOG(INFO) {
+          sb << "new AccountBlock for " << z.first.to_hex() << ": ";
+          block::gen::t_AccountBlock.print_ref(sb, cell);
+          csr->print_rec(sb);
+        };
       }
       if (!block::gen::t_AccountBlock.validate_ref(100000, cell)) {
-        block::gen::t_AccountBlock.print_ref(std::cerr, cell);
-        csr->print_rec(std::cerr);
+        FLOG(WARNING) {
+          sb << "AccountBlock failed to pass automatic validation tests: ";
+          block::gen::t_AccountBlock.print_ref(sb, cell);
+          csr->print_rec(sb);
+        };
         return fatal_error(std::string{"new AccountBlock for "} + z.first.to_hex() +
                            " failed to pass automatic validation tests");
       }
       if (!block::tlb::t_AccountBlock.validate_ref(100000, cell)) {
-        block::gen::t_AccountBlock.print_ref(std::cerr, cell);
-        csr->print_rec(std::cerr);
+        FLOG(WARNING) {
+          sb << "AccountBlock failed to pass handwritten validation tests: ";
+          block::gen::t_AccountBlock.print_ref(sb, cell);
+          csr->print_rec(sb);
+        };
         return fatal_error(std::string{"new AccountBlock for "} + z.first.to_hex() +
                            " failed to pass handwritten validation tests");
       }
@@ -2561,8 +2567,10 @@ bool Collator::combine_account_transactions() {
         } else if (acc.status == block::Account::acc_nonexist) {
           // account deleted
           if (verbosity > 2) {
-            std::cerr << "deleting account " << acc.addr.to_hex() << " with empty new value ";
-            block::gen::t_Account.print_ref(std::cerr, acc.total_state);
+            FLOG(INFO) {
+              sb << "deleting account " << acc.addr.to_hex() << " with empty new value ";
+              block::gen::t_Account.print_ref(sb, acc.total_state);
+            };
           }
           if (account_dict->lookup_delete(acc.addr).is_null()) {
             return fatal_error(std::string{"cannot delete account "} + acc.addr.to_hex() + " from ShardAccounts");
@@ -2570,8 +2578,10 @@ bool Collator::combine_account_transactions() {
         } else {
           // existing account modified
           if (verbosity > 4) {
-            std::cerr << "modifying account " << acc.addr.to_hex() << " to ";
-            block::gen::t_Account.print_ref(std::cerr, acc.total_state);
+            FLOG(INFO) {
+              sb << "modifying account " << acc.addr.to_hex() << " to ";
+              block::gen::t_Account.print_ref(sb, acc.total_state);
+            };
           }
           if (!(cb.store_ref_bool(acc.total_state)             // account_descr$_ account:^Account
                 && cb.store_bits_bool(acc.last_trans_hash_)    // last_trans_hash:bits256
@@ -2594,9 +2604,11 @@ bool Collator::combine_account_transactions() {
     return fatal_error("cannot serialize ShardAccountBlocks");
   }
   if (verbosity > 2) {
-    std::cerr << "new ShardAccountBlocks: ";
-    block::gen::t_ShardAccountBlocks.print_ref(std::cerr, shard_account_blocks_);
-    vm::load_cell_slice(shard_account_blocks_).print_rec(std::cerr);
+    FLOG(INFO) {
+      sb << "new ShardAccountBlocks: ";
+      block::gen::t_ShardAccountBlocks.print_ref(sb, shard_account_blocks_);
+      vm::load_cell_slice(shard_account_blocks_).print_rec(sb);
+    };
   }
   if (!block::gen::t_ShardAccountBlocks.validate_ref(100000, shard_account_blocks_)) {
     return fatal_error("new ShardAccountBlocks failed to pass automatic validity tests");
@@ -2606,9 +2618,11 @@ bool Collator::combine_account_transactions() {
   }
   auto shard_accounts = account_dict->get_root();
   if (verbosity > 2) {
-    std::cerr << "new ShardAccounts: ";
-    block::gen::t_ShardAccounts.print(std::cerr, *shard_accounts);
-    shard_accounts->print_rec(std::cerr);
+    FLOG(INFO) {
+      sb << "new ShardAccounts: ";
+      block::gen::t_ShardAccounts.print(sb, shard_accounts);
+      shard_accounts->print_rec(sb);
+    };
   }
   if (verify >= 2) {
     LOG(INFO) << "verifying new ShardAccounts";
@@ -2659,7 +2673,9 @@ bool Collator::create_special_transaction(block::CurrencyCollection amount, Ref<
                        addr.to_hex());
   }
   if (verbosity >= 4) {
-    block::gen::t_Message_Any.print_ref(std::cerr, msg);
+    FLOG(INFO) {
+      block::gen::t_Message_Any.print_ref(sb, msg);
+    };
   }
   CHECK(block::gen::t_Message_Any.validate_ref(msg));
   CHECK(block::tlb::t_Message.validate_ref(msg));
@@ -3163,8 +3179,10 @@ int Collator::process_one_new_message(block::NewOutMsg msg, bool enqueue_only, R
   Ref<vm::Cell> msg_env;
   CHECK(block::tlb::pack_cell(msg_env, msg_env_rec));
   if (verbosity > 2) {
-    std::cerr << "new (processed outbound) message envelope: ";
-    block::gen::t_MsgEnvelope.print_ref(std::cerr, msg_env);
+    FLOG(INFO) {
+      sb << "new (processed outbound) message envelope: ";
+      block::gen::t_MsgEnvelope.print_ref(sb, msg_env);
+    };
   }
   // 3. create InMsg, referring to this MsgEnvelope and this Transaction
   vm::CellBuilder cb;
@@ -3286,16 +3304,20 @@ bool Collator::enqueue_transit_message(Ref<vm::Cell> msg, Ref<vm::Cell> old_msg_
   Ref<vm::Cell> out_msg = cb.finalize();
   // 4.1. insert OutMsg into OutMsgDescr
   if (verbosity > 2) {
-    std::cerr << "OutMsg for a transit message: ";
-    block::gen::t_OutMsg.print_ref(std::cerr, out_msg);
+    FLOG(INFO) {
+      sb << "OutMsg for a transit message: ";
+      block::gen::t_OutMsg.print_ref(sb, out_msg);
+    };
   }
   if (!insert_out_msg(out_msg)) {
     return fatal_error("cannot insert a new OutMsg into OutMsgDescr");
   }
   // 4.2. insert InMsg into InMsgDescr
   if (verbosity > 2) {
-    std::cerr << "InMsg for a transit message: ";
-    block::gen::t_InMsg.print_ref(std::cerr, in_msg);
+    FLOG(INFO) {
+      sb << "InMsg for a transit message: ";
+      block::gen::t_InMsg.print_ref(sb, in_msg);
+    };
   }
   if (!insert_in_msg(in_msg)) {
     return fatal_error("cannot insert a new InMsg into InMsgDescr");
@@ -3366,7 +3388,10 @@ bool Collator::process_inbound_message(Ref<vm::CellSlice> enq_msg, ton::LogicalT
   if (enq_msg.is_null() || enq_msg->size_ext() != 0x10040 ||
       (enqueued_lt = enq_msg->prefetch_ulong(64)) < /* 0 */ 1 * lt) {  // DEBUG
     if (enq_msg.not_null()) {
-      block::gen::t_EnqueuedMsg.print(std::cerr, *enq_msg);
+      FLOG(WARNING) {
+        sb << "inbound internal message is not a valid EnqueuedMsg: ";
+        block::gen::t_EnqueuedMsg.print(sb, enq_msg);
+      };
     }
     LOG(ERROR) << "inbound internal message is not a valid EnqueuedMsg (created lt " << lt << ", enqueued "
                << enqueued_lt << ")";
@@ -3590,14 +3615,18 @@ bool Collator::process_inbound_internal_messages() {
     LOG(DEBUG) << "processing inbound message with (lt,hash)=(" << kv->lt << "," << kv->key.to_hex()
                << ") from neighbor #" << kv->source;
     if (verbosity > 2) {
-      std::cerr << "inbound message: lt=" << kv->lt << " from=" << kv->source << " key=" << kv->key.to_hex() << " msg=";
-      block::gen::t_EnqueuedMsg.print(std::cerr, *(kv->msg));
+      FLOG(INFO) {
+        sb << "inbound message: lt=" << kv->lt << " from=" << kv->source << " key=" << kv->key.to_hex() << " msg=";
+        block::gen::t_EnqueuedMsg.print(sb, kv->msg);
+      };
     }
     if (!process_inbound_message(kv->msg, kv->lt, kv->key.cbits(), neighbors_.at(kv->source))) {
       if (verbosity > 1) {
-        std::cerr << "invalid inbound message: lt=" << kv->lt << " from=" << kv->source << " key=" << kv->key.to_hex()
-                  << " msg=";
-        block::gen::t_EnqueuedMsg.print(std::cerr, *(kv->msg));
+        FLOG(INFO) {
+          sb << "invalid inbound message: lt=" << kv->lt << " from=" << kv->source << " key=" << kv->key.to_hex()
+                    << " msg=";
+          block::gen::t_EnqueuedMsg.print(sb, kv->msg);
+        };
       }
       return fatal_error("error processing inbound internal message");
     }
@@ -3884,7 +3913,10 @@ bool Collator::process_deferred_message(Ref<vm::CellSlice> enq_msg, StdSmcAddres
   LogicalTime enqueued_lt = 0;
   if (enq_msg.is_null() || enq_msg->size_ext() != 0x10040 || (enqueued_lt = enq_msg->prefetch_ulong(64)) != lt) {
     if (enq_msg.not_null()) {
-      block::gen::t_EnqueuedMsg.print(std::cerr, *enq_msg);
+      FLOG(WARNING) {
+        sb << "internal message in DispatchQueue is not a valid EnqueuedMsg: ";
+        block::gen::t_EnqueuedMsg.print(sb, enq_msg);
+      };
     }
     LOG(ERROR) << "internal message in DispatchQueue is not a valid EnqueuedMsg (created lt " << lt << ", enqueued "
                << enqueued_lt << ")";
@@ -3986,8 +4018,10 @@ bool Collator::process_deferred_message(Ref<vm::CellSlice> enq_msg, StdSmcAddres
  */
 bool Collator::insert_in_msg(Ref<vm::Cell> in_msg) {
   if (verbosity > 2) {
-    std::cerr << "InMsg being inserted into InMsgDescr: ";
-    block::gen::t_InMsg.print_ref(std::cerr, in_msg);
+    FLOG(INFO) {
+      sb << "InMsg being inserted into InMsgDescr: ";
+      block::gen::t_InMsg.print_ref(sb, in_msg);
+    };
   }
   auto cs = load_cell_slice(in_msg);
   if (!cs.size_refs()) {
@@ -4028,8 +4062,10 @@ bool Collator::insert_in_msg(Ref<vm::Cell> in_msg) {
  */
 bool Collator::insert_out_msg(Ref<vm::Cell> out_msg) {
   if (verbosity > 2) {
-    std::cerr << "OutMsg being inserted into OutMsgDescr: ";
-    block::gen::t_OutMsg.print_ref(std::cerr, out_msg);
+    FLOG(INFO) {
+      sb << "OutMsg being inserted into OutMsgDescr: ";
+      block::gen::t_OutMsg.print_ref(sb, out_msg);
+    };
   }
   auto cs = load_cell_slice(out_msg);
   if (!cs.size_refs()) {
@@ -4125,8 +4161,10 @@ bool Collator::enqueue_message(block::NewOutMsg msg, td::RefInt256 fwd_fees_rema
   }
   // 4. insert OutMsg into OutMsgDescr
   if (verbosity > 2) {
-    std::cerr << "OutMsg for a newly-generated message: ";
-    block::gen::t_OutMsg.print_ref(std::cerr, out_msg);
+    FLOG(INFO) {
+      sb << "OutMsg for a newly-generated message: ";
+      block::gen::t_OutMsg.print_ref(sb, out_msg);
+    };
   }
   if (!insert_out_msg(out_msg)) {
     return fatal_error("cannot insert a new OutMsg into OutMsgDescr");
@@ -4419,9 +4457,12 @@ bool Collator::create_mc_state_extra() {
   bool ignore_cfg_changes = false;
   Ref<vm::Cell> cfg0;
   if (!block::valid_config_data(cfg_smc_config, config_addr, true, true, old_mparams_)) {
-    block::gen::t_Hashmap_32_Ref_Cell.print_ref(std::cerr, cfg_smc_config);
     LOG(ERROR) << "configuration smart contract "s + config_addr.to_hex() +
                       " contains an invalid configuration in its data, IGNORING CHANGES";
+    FLOG(WARNING) {
+      sb << "ignored configuration: ";
+      block::gen::t_Hashmap_32_Ref_Cell.print_ref(sb, cfg_smc_config);
+    };
     ignore_cfg_changes = true;
   } else {
     cfg0 = cfg_dict.lookup_ref(td::BitArray<32>{(long long)0});
@@ -4459,34 +4500,26 @@ bool Collator::create_mc_state_extra() {
     return fatal_error(wset_res.move_as_error());
   }
   bool update_shard_cc = is_key_block_ || (now_ / ccvc.shard_cc_lifetime > prev_now_ / ccvc.shard_cc_lifetime);
-  // temp debug
-  if (verbosity >= 3 * 1) {
-    auto csr = shard_conf_->get_root_csr();
-    LOG(INFO) << "new shard configuration before post-processing is";
-    std::ostringstream os;
-    csr->print_rec(os);
-    block::gen::t_ShardHashes.print(os, csr.write());
-    LOG(INFO) << os.str();
-  }
-  // end (temp debug)
   if (!update_shard_config(wset_res.move_as_ok(), ccvc, update_shard_cc)) {
     auto csr = shard_conf_->get_root_csr();
     if (csr.is_null()) {
       LOG(WARNING) << "new shard configuration is null (!)";
     } else {
       LOG(WARNING) << "invalid new shard configuration is";
-      std::ostringstream os;
-      csr->print_rec(os);
-      block::gen::t_ShardHashes.print(os, csr.write());
-      LOG(WARNING) << os.str();
+      FLOG(WARNING) {
+        csr->print_rec(sb);
+        block::gen::t_ShardHashes.print(sb, csr);
+      };
     }
     return fatal_error("cannot post-process shard configuration");
   }
   // 3. save new shard_hashes
   state_extra.shard_hashes = shard_conf_->get_root_csr();
-  if (verbosity >= 3 * 0) {  // DEBUG
-    std::cerr << "updated shard configuration to ";
-    block::gen::t_ShardHashes.print(std::cerr, *state_extra.shard_hashes);
+  if (verbosity >= 3) {
+    FLOG(INFO) {
+      sb << "updated shard configuration to ";
+      block::gen::t_ShardHashes.print(sb, state_extra.shard_hashes);
+    };
   }
   if (!block::gen::t_ShardHashes.validate_upto(10000, *state_extra.shard_hashes)) {
     return fatal_error("new ShardHashes is invalid");
@@ -4587,13 +4620,18 @@ bool Collator::create_mc_state_extra() {
     if (verify >= 2) {
       LOG(INFO) << "verifying new BlockCreateStats";
       if (!block::gen::t_BlockCreateStats.validate_csr(100000, cs)) {
-        cs->print_rec(std::cerr);
-        block::gen::t_BlockCreateStats.print(std::cerr, *cs);
+        FLOG(WARNING) {
+          sb << "BlockCreateStats in the new masterchain state failed to pass automated validity checks: ";
+          cs->print_rec(sb);
+          block::gen::t_BlockCreateStats.print(sb, cs);
+        };
         return fatal_error("BlockCreateStats in the new masterchain state failed to pass automated validity checks");
       }
     }
     if (verbosity >= 4 * 1) {
-      block::gen::t_BlockCreateStats.print(std::cerr, *cs);
+      FLOG(INFO) {
+        block::gen::t_BlockCreateStats.print(sb, cs);
+      };
     }
   } else {
     state_extra.r1.block_create_stats.clear();
@@ -4628,7 +4666,6 @@ bool Collator::update_block_creator_count(td::ConstBitPtr key, unsigned shard_in
   if (!block::unpack_CreatorStats(std::move(cs), mc_cnt, shard_cnt)) {
     return fatal_error("cannot unpack CreatorStats for "s + key.to_hex(256) + " from previous masterchain state");
   }
-  // std::cerr << mc_cnt.to_str() << " " << shard_cnt.to_str() << std::endl;
   if (mc_incr && !mc_cnt.increase_by(mc_incr, now_)) {
     return fatal_error(PSTRING() << "cannot increase masterchain block counter in CreatorStats for " << key.to_hex(256)
                                  << " by " << mc_incr << " (old value is " << mc_cnt.to_str() << ")");
@@ -4999,9 +5036,11 @@ bool Collator::update_public_libraries() {
     }
   }
   if (libraries_changed_ && verbosity >= 2) {
-    std::cerr << "New public libraries: ";
-    block::gen::t_HashmapE_256_LibDescr.print(std::cerr, shard_libraries_->get_root());
-    shard_libraries_->get_root()->print_rec(std::cerr);
+    FLOG(INFO) {
+      sb << "New public libraries: ";
+      block::gen::t_HashmapE_256_LibDescr.print(sb, shard_libraries_->get_root());
+      shard_libraries_->get_root()->print_rec(sb);
+    };
   }
   return true;
 }
@@ -5124,9 +5163,11 @@ bool Collator::create_shard_state() {
   }
   LOG(DEBUG) << "min_ref_mc_seqno is " << min_ref_mc_seqno_;
   if (verbosity > 2) {
-    std::cerr << "new ShardState: ";
-    block::gen::t_ShardState.print_ref(std::cerr, state_root);
-    vm::load_cell_slice(state_root).print_rec(std::cerr);
+    FLOG(INFO) {
+      sb << "new ShardState: ";
+      block::gen::t_ShardState.print_ref(sb, state_root);
+      vm::load_cell_slice(state_root).print_rec(sb);
+    };
   }
   if (verify >= 2) {
     LOG(INFO) << "verifying new ShardState";
@@ -5139,9 +5180,11 @@ bool Collator::create_shard_state() {
     return fatal_error("cannot create Merkle update for ShardState");
   }
   if (verbosity > 2) {
-    std::cerr << "Merkle Update for ShardState: ";
-    vm::CellSlice cs{vm::NoVm{}, state_update};
-    cs.print_rec(std::cerr);
+    FLOG(INFO) {
+      sb << "Merkle Update for ShardState: ";
+      vm::CellSlice cs{vm::NoVm{}, state_update};
+      cs.print_rec(sb);
+    };
   }
   LOG(INFO) << "updating block profile statistics";
   block_limit_status_->add_proof(state_root);
@@ -5186,10 +5229,12 @@ bool Collator::update_processed_upto() {
  */
 bool Collator::compute_out_msg_queue_info(Ref<vm::Cell>& out_msg_queue_info) {
   if (verbosity >= 2) {
-    auto rt = out_msg_queue_->get_root();
-    std::cerr << "resulting out_msg_queue is ";
-    block::gen::t_OutMsgQueue.print(std::cerr, *rt);
-    rt->print_rec(std::cerr);
+    FLOG(INFO) {
+      auto rt = out_msg_queue_->get_root();
+      sb << "resulting out_msg_queue is ";
+      block::gen::t_OutMsgQueue.print(sb, rt);
+      rt->print_rec(sb);
+    };
   }
   vm::CellBuilder cb;
   // out_msg_queue_extra#0 dispatch_queue:DispatchQueue out_queue_size:(Maybe uint48) = OutMsgQueueExtra;
@@ -5239,8 +5284,10 @@ bool Collator::compute_total_balance() {
   }
   vm::CellSlice cs{*(in_msg_dict->get_root_extra())};
   if (verbosity > 2) {
-    block::gen::t_ImportFees.print(std::cerr, vm::CellSlice{*(in_msg_dict->get_root_extra())});
-    cs.print_rec(std::cerr);
+    FLOG(INFO) {
+      block::gen::t_ImportFees.print(sb, in_msg_dict->get_root_extra());
+      cs.print_rec(sb);
+    };
   }
   auto new_import_fees = block::tlb::t_Grams.as_integer_skip(cs);
   if (new_import_fees.is_null()) {
@@ -5468,9 +5515,11 @@ bool Collator::create_block() {
     return fatal_error("cannot create new Block");
   }
   if (verbosity >= 3 * 1) {
-    std::cerr << "new Block: ";
-    block::gen::t_Block.print_ref(std::cerr, new_block);
-    vm::load_cell_slice(new_block).print_rec(std::cerr);
+    FLOG(INFO) {
+      sb << "new Block: ";
+      block::gen::t_Block.print_ref(sb, new_block);
+      vm::load_cell_slice(new_block).print_rec(sb);
+    };
   }
   if (verify >= 1) {
     LOG(INFO) << "verifying new Block";
@@ -5508,9 +5557,11 @@ Ref<vm::Cell> Collator::collate_shard_block_descr_set() {
     return {};
   }
   if (verbosity >= 4 * 1) {
-    std::cerr << "serialized TopBlockDescrSet for collated data is: ";
-    block::gen::t_TopBlockDescrSet.print_ref(std::cerr, cell);
-    vm::load_cell_slice(cell).print_rec(std::cerr);
+    FLOG(INFO) {
+      sb << "serialized TopBlockDescrSet for collated data is: ";
+      block::gen::t_TopBlockDescrSet.print_ref(sb, cell);
+      vm::load_cell_slice(cell).print_rec(sb);
+    };
   }
   return cell;
 }
@@ -5717,8 +5768,10 @@ td::Result<bool> Collator::register_external_message_cell(Ref<vm::Cell> ext_msg,
     return td::Status::Error("inbound external message has destination address not in this shard");
   }
   if (verbosity > 2) {
-    std::cerr << "registered external message: ";
-    block::gen::t_Message_Any.print_ref(std::cerr, ext_msg);
+    FLOG(INFO) {
+      sb << "registered external message: ";
+      block::gen::t_Message_Any.print_ref(sb, ext_msg);
+    };
   }
   ext_msg_map.emplace(hash, 1);
   ext_msg_list_.push_back({std::move(ext_msg), ext_hash, priority});
diff --git a/validator/impl/liteserver.cpp b/validator/impl/liteserver.cpp
index 723dbfe97..83f39c455 100644
--- a/validator/impl/liteserver.cpp
+++ b/validator/impl/liteserver.cpp
@@ -85,19 +85,13 @@ void LiteQuery::abort_query(td::Status reason) {
   if (acc_state_promise_) {
     acc_state_promise_.set_error(std::move(reason));
   } else if (promise_) {
+    td::actor::send_closure(manager_, &ValidatorManager::add_lite_query_stats, query_obj_ ? query_obj_->get_id() : 0,
+                            false);
     promise_.set_error(std::move(reason));
   }
   stop();
 }
 
-void LiteQuery::abort_query_ext(td::Status reason, std::string comment) {
-  LOG(INFO) << "aborted liteserver query: " << comment << " : " << reason.to_string();
-  if (promise_) {
-    promise_.set_error(reason.move_as_error_prefix(comment + " : "));
-  }
-  stop();
-}
-
 bool LiteQuery::fatal_error(td::Status error) {
   abort_query(std::move(error));
   return false;
@@ -120,6 +114,8 @@ bool LiteQuery::finish_query(td::BufferSlice result, bool skip_cache_update) {
     td::actor::send_closure(cache_, &LiteServerCache::update, cache_key_, result.clone());
   }
   if (promise_) {
+    td::actor::send_closure(manager_, &ValidatorManager::add_lite_query_stats, query_obj_ ? query_obj_->get_id() : 0,
+                            true);
     promise_.set_result(std::move(result));
     stop();
     return true;
@@ -139,7 +135,6 @@ void LiteQuery::start_up() {
 
   auto F = fetch_tl_object<ton::lite_api::Function>(query_, true);
   if (F.is_error()) {
-    td::actor::send_closure(manager_, &ValidatorManager::add_lite_query_stats, 0);  // unknown
     abort_query(F.move_as_error());
     return;
   }
@@ -192,7 +187,6 @@ bool LiteQuery::use_cache()  {
 }
 
 void LiteQuery::perform() {
-  td::actor::send_closure(manager_, &ValidatorManager::add_lite_query_stats, query_obj_->get_id());
   lite_api::downcast_call(
       *query_obj_,
       td::overloaded(
diff --git a/validator/impl/liteserver.hpp b/validator/impl/liteserver.hpp
index 447e1dad4..fc8735332 100644
--- a/validator/impl/liteserver.hpp
+++ b/validator/impl/liteserver.hpp
@@ -97,7 +97,6 @@ class LiteQuery : public td::actor::Actor {
   bool fatal_error(std::string err_msg, int err_code = -400);
   bool fatal_error(int err_code, std::string err_msg = "");
   void abort_query(td::Status reason);
-  void abort_query_ext(td::Status reason, std::string err_msg);
   bool finish_query(td::BufferSlice result, bool skip_cache_update = false);
   void alarm() override;
   void start_up() override;
diff --git a/validator/impl/signature-set.cpp b/validator/impl/signature-set.cpp
index c72982167..0078a115b 100644
--- a/validator/impl/signature-set.cpp
+++ b/validator/impl/signature-set.cpp
@@ -42,9 +42,6 @@ td::BufferSlice BlockSignatureSetQ::serialize() const {
   }
   Ref<vm::Cell> root;
   CHECK(serialize_to(root));
-  //std::cerr << "serializing BlockSignatureSet: ";
-  //vm::CellSlice{vm::NoVm{}, root}.print_rec(std::cerr);
-  //std::cerr << std::endl;
   auto res = vm::std_boc_serialize(std::move(root));
   LOG_CHECK(res.is_ok()) << res.move_as_error();
   return res.move_as_ok();
diff --git a/validator/impl/top-shard-descr.cpp b/validator/impl/top-shard-descr.cpp
index 8ff8862d6..9eadeef35 100644
--- a/validator/impl/top-shard-descr.cpp
+++ b/validator/impl/top-shard-descr.cpp
@@ -175,9 +175,11 @@ td::Status ShardTopBlockDescrQ::unpack() {
   block::gen::TopBlockDescr::Record rec;
   if (!(block::gen::t_TopBlockDescr.force_validate_ref(root_) && tlb::unpack_cell(root_, rec) &&
         block::tlb::t_BlockIdExt.unpack(rec.proof_for.write(), block_id_))) {
-    std::cerr << "invalid ShardTopBlockDescr: ";
-    block::gen::t_TopBlockDescr.print_ref(std::cerr, root_);
-    vm::load_cell_slice(root_).print_rec(std::cerr);
+    FLOG(INFO) {
+      sb << "invalid ShardTopBlockDescr: ";
+      block::gen::t_TopBlockDescr.print_ref(sb, root_);
+      vm::load_cell_slice(root_).print_rec(sb);
+    };
     return td::Status::Error(-666, "Shard top block description is not a valid TopBlockDescr TL-B object");
   }
   LOG(DEBUG) << "unpacking a ShardTopBlockDescr for " << block_id_.to_str() << " with " << rec.len << " links";
diff --git a/validator/impl/validate-query.cpp b/validator/impl/validate-query.cpp
index 9e4d406e6..31c30e906 100644
--- a/validator/impl/validate-query.cpp
+++ b/validator/impl/validate-query.cpp
@@ -115,7 +115,7 @@ bool ValidateQuery::reject_query(std::string error, td::BufferSlice reason) {
   error = error_ctx() + error;
   LOG(ERROR) << "REJECT: aborting validation of block candidate for " << shard_.to_str() << " : " << error;
   if (main_promise) {
-    record_stats();
+    record_stats(false);
     errorlog::ErrorLog::log(PSTRING() << "REJECT: aborting validation of block candidate for " << shard_.to_str()
                                       << " : " << error << ": data=" << block_candidate.id.file_hash.to_hex()
                                       << " collated_data=" << block_candidate.collated_file_hash.to_hex());
@@ -153,7 +153,7 @@ bool ValidateQuery::soft_reject_query(std::string error, td::BufferSlice reason)
   error = error_ctx() + error;
   LOG(ERROR) << "SOFT REJECT: aborting validation of block candidate for " << shard_.to_str() << " : " << error;
   if (main_promise) {
-    record_stats();
+    record_stats(false);
     errorlog::ErrorLog::log(PSTRING() << "SOFT REJECT: aborting validation of block candidate for " << shard_.to_str()
                                       << " : " << error << ": data=" << block_candidate.id.file_hash.to_hex()
                                       << " collated_data=" << block_candidate.collated_file_hash.to_hex());
@@ -176,7 +176,7 @@ bool ValidateQuery::fatal_error(td::Status error) {
   error.ensure_error();
   LOG(ERROR) << "aborting validation of block candidate for " << shard_.to_str() << " : " << error.to_string();
   if (main_promise) {
-    record_stats();
+    record_stats(false);
     auto c = error.code();
     if (c <= -667 && c >= -670) {
       errorlog::ErrorLog::log(PSTRING() << "FATAL ERROR: aborting validation of block candidate for " << shard_.to_str()
@@ -234,7 +234,7 @@ bool ValidateQuery::fatal_error(std::string err_msg, int err_code) {
  */
 void ValidateQuery::finish_query() {
   if (main_promise) {
-    record_stats();
+    record_stats(true);
     LOG(WARNING) << "validate query done";
     main_promise.set_result(now_);
   }
@@ -1553,8 +1553,10 @@ void ValidateQuery::got_neighbor_out_queue(int i, td::Result<Ref<MessageQueue>>
   // unpack ProcessedUpto
   LOG(DEBUG) << "unpacking ProcessedUpto of neighbor " << descr.blk_.to_str();
   if (verbosity >= 2) {
-    block::gen::t_ProcessedInfo.print(std::cerr, qinfo.proc_info);
-    qinfo.proc_info->print_rec(std::cerr);
+    FLOG(INFO) {
+      block::gen::t_ProcessedInfo.print(sb, qinfo.proc_info);
+      qinfo.proc_info->print_rec(sb);
+    };
   }
   descr.processed_upto = block::MsgProcessedUptoCollection::unpack(descr.shard(), qinfo.proc_info);
   if (!descr.processed_upto) {
@@ -2656,7 +2658,6 @@ bool ValidateQuery::unpack_precheck_value_flow(Ref<vm::Cell> value_flow_root) {
                         " but the sum over all accounts present in the new state is " + cc.to_str());
   }
   auto msg_extra = in_msg_dict_->get_root_extra();
-  // block::gen::t_ImportFees.print(std::cerr, msg_extra);
   if (!(block::tlb::t_Grams.as_integer_skip_to(msg_extra.write(), import_fees_) && cc.unpack(std::move(msg_extra)))) {
     return reject_query("cannot unpack ImportFees from the augmentation of the InMsgDescr dictionary");
   }
@@ -2760,20 +2761,22 @@ bool ValidateQuery::precheck_one_account_update(td::ConstBitPtr acc_id, Ref<vm::
   auto acc_blk_root = account_blocks_dict_->lookup(acc_id, 256);
   if (acc_blk_root.is_null()) {
     if (verbosity >= 3 * 0) {
-      std::cerr << "state of account " << workchain() << ":" << acc_id.to_hex(256)
-                << " in the old shardchain state:" << std::endl;
-      if (old_value.not_null()) {
-        block::gen::t_ShardAccount.print(std::cerr, *old_value);
-      } else {
-        std::cerr << "<absent>" << std::endl;
-      }
-      std::cerr << "state of account " << workchain() << ":" << acc_id.to_hex(256)
-                << " in the new shardchain state:" << std::endl;
-      if (new_value.not_null()) {
-        block::gen::t_ShardAccount.print(std::cerr, *new_value);
-      } else {
-        std::cerr << "<absent>" << std::endl;
-      }
+      FLOG(INFO) {
+        sb << "state of account " << workchain() << ":" << acc_id.to_hex(256)
+                  << " in the old shardchain state:" << "\n";
+        if (old_value.not_null()) {
+          block::gen::t_ShardAccount.print(sb, old_value);
+        } else {
+          sb << "<absent>" << "\n";
+        }
+        sb << "state of account " << workchain() << ":" << acc_id.to_hex(256)
+                  << " in the new shardchain state:" << "\n";
+        if (new_value.not_null()) {
+          block::gen::t_ShardAccount.print(sb, new_value);
+        } else {
+          sb << "<absent>" << "\n";
+        }
+      };
     }
     return reject_query("the state of account "s + acc_id.to_hex(256) +
                         " changed in the new state with respect to the old state, but the block contains no "
@@ -2931,8 +2934,6 @@ bool ValidateQuery::precheck_one_account_block(td::ConstBitPtr acc_id, Ref<vm::C
                         " not belonging to the block's shard " + shard_.to_str());
   }
   CHECK(acc_blk_root.not_null());
-  // acc_blk_root->print_rec(std::cerr);
-  // block::gen::t_AccountBlock.print(std::cerr, acc_blk_root);
   block::gen::AccountBlock::Record acc_blk;
   block::gen::HASH_UPDATE::Record hash_upd;
   if (!(tlb::csr_unpack(acc_blk_root, acc_blk) &&
@@ -3860,7 +3861,9 @@ bool ValidateQuery::check_in_msg(td::ConstBitPtr key, Ref<vm::CellSlice> in_msg)
     ton::LogicalTime trans_lt;
     CHECK(block::get_transaction_id(transaction, trans_addr, trans_lt));
     if (dest_addr != trans_addr) {
-      block::gen::t_InMsg.print(std::cerr, *in_msg);
+      FLOG(INFO) {
+        block::gen::t_InMsg.print(sb, in_msg);
+      };
       return reject_query(PSTRING() << "InMsg corresponding to inbound message with hash " << key.to_hex(256)
                                     << " and destination address " << dest_addr.to_hex()
                                     << " claims that the message is processed by transaction " << trans_lt
@@ -4408,7 +4411,9 @@ bool ValidateQuery::check_out_msg(td::ConstBitPtr key, Ref<vm::CellSlice> out_ms
     ton::LogicalTime trans_lt;
     CHECK(block::get_transaction_id(transaction, trans_addr, trans_lt));
     if (src_addr != trans_addr) {
-      block::gen::t_OutMsg.print(std::cerr, *out_msg);
+      FLOG(INFO) {
+        block::gen::t_OutMsg.print(sb, out_msg);
+      };
       return reject_query(PSTRING() << "OutMsg corresponding to outbound message with hash " << key.to_hex(256)
                                     << " and source address " << src_addr.to_hex()
                                     << " claims that the message was created by transaction " << trans_lt
@@ -5022,15 +5027,19 @@ bool ValidateQuery::check_in_queue() {
     LOG(DEBUG) << "processing inbound message with (lt,hash)=(" << kv->lt << "," << kv->key.to_hex()
                << ") from neighbor #" << kv->source;
     if (verbosity > 3) {
-      std::cerr << "inbound message: lt=" << kv->lt << " from=" << kv->source << " key=" << kv->key.to_hex() << " msg=";
-      block::gen::t_EnqueuedMsg.print(std::cerr, *(kv->msg));
+      FLOG(INFO) {
+        sb << "inbound message: lt=" << kv->lt << " from=" << kv->source << " key=" << kv->key.to_hex() << " msg=";
+        block::gen::t_EnqueuedMsg.print(sb, kv->msg);
+      };
     }
     bool unprocessed = false;
     if (!check_neighbor_outbound_message(kv->msg, kv->lt, kv->key.cbits(), neighbors_.at(kv->source), unprocessed)) {
       if (verbosity > 1) {
-        std::cerr << "invalid neighbor outbound message: lt=" << kv->lt << " from=" << kv->source
-                  << " key=" << kv->key.to_hex() << " msg=";
-        block::gen::t_EnqueuedMsg.print(std::cerr, *(kv->msg));
+        FLOG(INFO) {
+          sb << "invalid neighbor outbound message: lt=" << kv->lt << " from=" << kv->source
+             << " key=" << kv->key.to_hex() << " msg=";
+          block::gen::t_EnqueuedMsg.print(sb, kv->msg);
+        };
       }
       return reject_query("error processing outbound internal message "s + kv->key.to_hex() + " of neighbor " +
                           neighbors_.at(kv->source).blk_.to_str());
@@ -5636,10 +5645,12 @@ bool ValidateQuery::check_one_transaction(block::Account& account, ton::LogicalT
   // now compare the re-created transaction with the one we have
   if (trans_root2->get_hash() != trans_root->get_hash()) {
     if (verbosity >= 3 * 0) {
-      std::cerr << "original transaction " << lt << " of " << addr.to_hex() << ": ";
-      block::gen::t_Transaction.print_ref(std::cerr, trans_root);
-      std::cerr << "re-created transaction " << lt << " of " << addr.to_hex() << ": ";
-      block::gen::t_Transaction.print_ref(std::cerr, trans_root2);
+      FLOG(INFO) {
+        sb << "original transaction " << lt << " of " << addr.to_hex() << ": ";
+        block::gen::t_Transaction.print_ref(sb, trans_root);
+        sb << "re-created transaction " << lt << " of " << addr.to_hex() << ": ";
+        block::gen::t_Transaction.print_ref(sb, trans_root2);
+      };
     }
     return reject_query(PSTRING() << "the transaction " << lt << " of " << addr.to_hex() << " has hash "
                                   << trans_root->get_hash().to_hex()
@@ -6917,13 +6928,13 @@ void ValidateQuery::written_candidate() {
 /**
  * Sends validation work time to manager.
  */
-void ValidateQuery::record_stats() {
+void ValidateQuery::record_stats(bool success) {
   double work_time = work_timer_.elapsed();
   double cpu_work_time = cpu_work_timer_.elapsed();
   LOG(WARNING) << "validation took " << perf_timer_.elapsed() << "s";
   LOG(WARNING) << "Validate query work time = " << work_time << "s, cpu time = " << cpu_work_time << "s";
   td::actor::send_closure(manager, &ValidatorManager::record_validate_query_stats, block_candidate.id, work_time,
-                          cpu_work_time);
+                          cpu_work_time, success);
 }
 
 }  // namespace validator
diff --git a/validator/impl/validate-query.hpp b/validator/impl/validate-query.hpp
index 98cd2493b..90c368ffb 100644
--- a/validator/impl/validate-query.hpp
+++ b/validator/impl/validate-query.hpp
@@ -400,7 +400,7 @@ class ValidateQuery : public td::actor::Actor {
 
   td::Timer work_timer_{true};
   td::ThreadCpuTimer cpu_work_timer_{true};
-  void record_stats();
+  void record_stats(bool success);
 };
 
 }  // namespace validator
diff --git a/validator/interfaces/validator-manager.h b/validator/interfaces/validator-manager.h
index 20d4bd62c..00fb77e1e 100644
--- a/validator/interfaces/validator-manager.h
+++ b/validator/interfaces/validator-manager.h
@@ -205,13 +205,13 @@ class ValidatorManager : public ValidatorManagerInterface {
       td::optional<ShardIdFull> shard,
       td::Promise<tl_object_ptr<lite_api::liteServer_nonfinal_validatorGroups>> promise) = 0;
 
-  virtual void add_lite_query_stats(int lite_query_id) {
+  virtual void add_lite_query_stats(int lite_query_id, bool success) {
   }
 
   virtual void record_collate_query_stats(BlockIdExt block_id, double work_time, double cpu_work_time,
-                                          CollationStats stats) {
+                                          td::optional<CollationStats> stats) {
   }
-  virtual void record_validate_query_stats(BlockIdExt block_id, double work_time, double cpu_work_time) {
+  virtual void record_validate_query_stats(BlockIdExt block_id, double work_time, double cpu_work_time, bool success) {
   }
 
   virtual void add_persistent_state_description(td::Ref<PersistentStateDescription> desc) = 0;
diff --git a/validator/manager-init.cpp b/validator/manager-init.cpp
index c2944b257..6f304680b 100644
--- a/validator/manager-init.cpp
+++ b/validator/manager-init.cpp
@@ -32,6 +32,8 @@ namespace ton {
 namespace validator {
 
 void ValidatorManagerMasterchainReiniter::start_up() {
+  status_ = ProcessStatus(manager_, "process.initial_sync");
+  status_.set_status(PSTRING() << "starting, init block seqno " << block_id_.seqno());
   LOG(INFO) << "init_block_id=" << block_id_;
   CHECK(block_id_.is_masterchain());
   CHECK(block_id_.id.shard == shardIdAll);
@@ -58,6 +60,7 @@ void ValidatorManagerMasterchainReiniter::got_masterchain_handle(BlockHandle han
   key_blocks_.push_back(handle_);
 
   if (opts_->initial_sync_disabled()) {
+    status_.set_status(PSTRING() << "downloading masterchain state " << handle_->id().seqno());
     auto P = td::PromiseCreator::lambda([SelfId = actor_id(this)](td::Result<td::Ref<ShardState>> R) {
       R.ensure();
       td::actor::send_closure(SelfId, &ValidatorManagerMasterchainReiniter::download_masterchain_state);
@@ -181,6 +184,7 @@ void ValidatorManagerMasterchainReiniter::got_next_key_blocks(std::vector<BlockI
     }
   }
   LOG(WARNING) << "last key block is " << vec[vec.size() - 1];
+  status_.set_status(PSTRING() << "last key block is " << vec.back().seqno());
   auto s = static_cast<td::uint32>(key_blocks_.size());
   key_blocks_.resize(key_blocks_.size() + vec.size(), nullptr);
 
@@ -247,6 +251,7 @@ void ValidatorManagerMasterchainReiniter::choose_masterchain_state() {
 }
 
 void ValidatorManagerMasterchainReiniter::download_masterchain_state() {
+  status_.set_status(PSTRING() << "downloading masterchain state " << block_id_.seqno());
   auto P = td::PromiseCreator::lambda([SelfId = actor_id(this)](td::Result<td::Ref<ShardState>> R) {
     if (R.is_error()) {
       LOG(WARNING) << "failed to download masterchain state: " << R.move_as_error();
@@ -274,6 +279,7 @@ void ValidatorManagerMasterchainReiniter::downloaded_masterchain_state(td::Ref<S
     td::actor::send_closure(SelfId, &ValidatorManagerMasterchainReiniter::downloaded_all_shards);
   });
   client_ = td::actor::create_actor<ShardClient>("shardclient", opts_, handle_, state_, manager_, std::move(P));
+  status_.set_status(PSTRING() << "downloading all shard states, mc seqno " << block_id_.seqno());
 }
 
 void ValidatorManagerMasterchainReiniter::downloaded_all_shards() {
diff --git a/validator/manager-init.hpp b/validator/manager-init.hpp
index 7dce4e47a..901b826bd 100644
--- a/validator/manager-init.hpp
+++ b/validator/manager-init.hpp
@@ -27,6 +27,8 @@
 
 #include "manager-init.h"
 
+#include <stats-provider.h>
+
 namespace ton {
 
 namespace validator {
@@ -77,6 +79,8 @@ class ValidatorManagerMasterchainReiniter : public td::actor::Actor {
 
   td::uint32 pending_ = 0;
   td::actor::ActorOwn<ShardClient> client_;
+
+  ProcessStatus status_;
 };
 
 class ValidatorManagerMasterchainStarter : public td::actor::Actor {
diff --git a/validator/manager.cpp b/validator/manager.cpp
index 068ea5eb1..b0ac54092 100644
--- a/validator/manager.cpp
+++ b/validator/manager.cpp
@@ -430,6 +430,10 @@ void ValidatorManagerImpl::add_external_message(td::Ref<ExtMessage> msg, int pri
   ext_messages_hashes_[id.hash] = {priority, id};
 }
 void ValidatorManagerImpl::check_external_message(td::BufferSlice data, td::Promise<td::Ref<ExtMessage>> promise) {
+  if (!started_) {
+    promise.set_error(td::Status::Error(ErrorCode::notready, "node not synced"));
+    return;
+  }
   auto state = do_get_last_liteserver_state();
   if (state.is_null()) {
     promise.set_error(td::Status::Error(ErrorCode::notready, "not ready"));
@@ -451,11 +455,9 @@ void ValidatorManagerImpl::check_external_message(td::BufferSlice data, td::Prom
 
   promise = [self = this, wc, addr, promise = std::move(promise),
              SelfId = actor_id(this)](td::Result<td::Ref<ExtMessage>> R) mutable {
-    if (R.is_error()) {
-      promise.set_error(R.move_as_error());
-      return;
-    }
-    td::actor::send_lambda(SelfId, [=, promise = std::move(promise), message = R.move_as_ok()]() mutable {
+    td::actor::send_lambda(SelfId, [=, promise = std::move(promise), R = std::move(R)]() mutable {
+      ++(R.is_ok() ? self->total_check_ext_messages_ok_ : self->total_check_ext_messages_error_);
+      TRY_RESULT_PROMISE(promise, message, std::move(R));
       if (self->checked_ext_msg_counter_.inc_msg_count(wc, addr) > max_ext_msg_per_addr()) {
         promise.set_error(
             td::Status::Error(PSTRING() << "too many external messages to address " << wc << ":" << addr.to_hex()));
@@ -698,11 +700,10 @@ void ValidatorManagerImpl::wait_block_state(BlockHandle handle, td::uint32 prior
     auto P = td::PromiseCreator::lambda([SelfId = actor_id(this), handle](td::Result<td::Ref<ShardState>> R) {
       td::actor::send_closure(SelfId, &ValidatorManagerImpl::finished_wait_state, handle, std::move(R));
     });
-    auto id =
-        td::actor::create_actor<WaitBlockState>("waitstate", handle, priority, actor_id(this),
-                                                td::Timestamp::at(timeout.at() + 10.0), std::move(P),
-                                                get_block_persistent_state(handle->id()))
-            .release();
+    auto id = td::actor::create_actor<WaitBlockState>("waitstate", handle, priority, actor_id(this),
+                                                      td::Timestamp::at(timeout.at() + 10.0), std::move(P),
+                                                      get_block_persistent_state_to_download(handle->id()))
+                  .release();
     wait_state_[handle->id()].actor_ = id;
     it = wait_state_.find(handle->id());
   }
@@ -1148,9 +1149,10 @@ void ValidatorManagerImpl::finished_wait_state(BlockHandle handle, td::Result<td
         auto P = td::PromiseCreator::lambda([SelfId = actor_id(this), handle](td::Result<td::Ref<ShardState>> R) {
           td::actor::send_closure(SelfId, &ValidatorManagerImpl::finished_wait_state, handle, std::move(R));
         });
-        auto id = td::actor::create_actor<WaitBlockState>("waitstate", handle, X.second, actor_id(this), X.first,
-                                                          std::move(P), get_block_persistent_state(handle->id()))
-                      .release();
+        auto id =
+            td::actor::create_actor<WaitBlockState>("waitstate", handle, X.second, actor_id(this), X.first,
+                                                    std::move(P), get_block_persistent_state_to_download(handle->id()))
+                .release();
         it->second.actor_ = id;
         return;
       }
@@ -2131,7 +2133,7 @@ void ValidatorManagerImpl::update_shards() {
     }
   }
 
-  bool validating_masterchain = false;
+  active_validator_groups_master_ = active_validator_groups_shard_ = 0;
   if (allow_validate_) {
     for (auto &desc : new_shards) {
       auto shard = desc.first;
@@ -2148,9 +2150,7 @@ void ValidatorManagerImpl::update_shards() {
       auto validator_id = get_validator(shard, val_set);
 
       if (!validator_id.is_zero()) {
-        if (shard.is_masterchain()) {
-          validating_masterchain = true;
-        }
+        ++(shard.is_masterchain() ? active_validator_groups_master_ : active_validator_groups_shard_);
         auto val_group_id = get_validator_set_id(shard, val_set, opts_hash, key_seqno, opts);
 
         if (force_recover) {
@@ -2845,8 +2845,8 @@ void ValidatorManagerImpl::prepare_stats(td::Promise<std::vector<std::pair<std::
     vec.emplace_back("knownkeymasterchainblock", last_known_key_block_handle_->id().to_str());
     vec.emplace_back("rotatemasterchainblock", last_rotate_block_id_.to_str());
     //vec.emplace_back("shardclientmasterchainseqno", td::to_string(min_confirmed_masterchain_seqno_));
-    vec.emplace_back("stateserializermasterchainseqno", td::to_string(state_serializer_masterchain_seqno_));
   }
+
   td::NamedThreadSafeCounter::get_default().for_each([&](auto key, auto value) {
     vec.emplace_back("counter." + key, PSTRING() << value);
   });
@@ -2864,9 +2864,48 @@ void ValidatorManagerImpl::prepare_stats(td::Promise<std::vector<std::pair<std::
     td::actor::send_closure(shard_client_, &ShardClient::get_processed_masterchain_block, std::move(P));
   }
 
+  vec.emplace_back("start_time", td::to_string(started_at_));
+  for (int iter = 0; iter < 2; ++iter) {
+    td::StringBuilder sb;
+    td::uint32 total = 0;
+    for (const auto &p : (iter ? total_ls_queries_error_ : total_ls_queries_ok_)) {
+      sb << lite_query_name_by_id(p.first) << ":" << p.second << " ";
+      total += p.second;
+    }
+    sb << "TOTAL:" << total;
+    vec.emplace_back(PSTRING() << "total.ls_queries_" << (iter ? "error" : "ok"), sb.as_cslice().str());
+  }
+  vec.emplace_back("total.ext_msg_check",
+                   PSTRING() << "ok:" << total_check_ext_messages_ok_ << " error:" << total_check_ext_messages_error_);
+  vec.emplace_back("total.collated_blocks.master", PSTRING() << "ok:" << total_collated_blocks_master_ok_
+                                                             << " error:" << total_collated_blocks_master_error_);
+  vec.emplace_back("total.collated_blocks.shard", PSTRING() << "ok:" << total_collated_blocks_shard_ok_
+                                                            << " error:" << total_collated_blocks_shard_error_);
+  vec.emplace_back("total.validated_blocks.master", PSTRING() << "ok:" << total_validated_blocks_master_ok_
+                                                              << " error:" << total_validated_blocks_master_error_);
+  vec.emplace_back("total.validated_blocks.shard", PSTRING() << "ok:" << total_validated_blocks_shard_ok_
+                                                             << " error:" << total_validated_blocks_shard_error_);
+  if (is_validator()) {
+    vec.emplace_back("active_validator_groups", PSTRING() << "master:" << active_validator_groups_master_
+                                                          << " shard:" << active_validator_groups_shard_);
+  }
+
+  bool serializer_enabled = opts_->get_state_serializer_enabled();
+  if (is_validator() && last_masterchain_state_->get_global_id() == -239) {
+    serializer_enabled = false;
+  }
+  vec.emplace_back("stateserializerenabled", serializer_enabled ? "true" : "false");
+
   merger.make_promise("").set_value(std::move(vec));
 
+  if (!serializer_.empty()) {
+    td::actor::send_closure(serializer_, &AsyncStateSerializer::prepare_stats, merger.make_promise(""));
+  }
+
   td::actor::send_closure(db_, &Db::prepare_stats, merger.make_promise("db."));
+  for (auto &[_, p] : stats_providers_) {
+    p.second(merger.make_promise(p.first));
+  }
 }
 
 void ValidatorManagerImpl::prepare_perf_timer_stats(td::Promise<std::vector<PerfTimerStats>> promise) {
@@ -3336,11 +3375,18 @@ void ValidatorManagerImpl::got_persistent_state_descriptions(std::vector<td::Ref
   }
 }
 
-td::Ref<PersistentStateDescription> ValidatorManagerImpl::get_block_persistent_state(BlockIdExt block_id) {
+td::Ref<PersistentStateDescription> ValidatorManagerImpl::get_block_persistent_state_to_download(BlockIdExt block_id) {
+  if (block_id.is_masterchain()) {
+    return {};
+  }
   auto it = persistent_state_blocks_.find(block_id);
   if (it == persistent_state_blocks_.end()) {
     return {};
   }
+  if (it->second->masterchain_id.seqno() + 16 >= min_confirmed_masterchain_seqno_) {
+    // Do not download persistent states during ordinary shard client sync
+    return {};
+  }
   return it->second;
 }
 
@@ -3353,17 +3399,28 @@ td::actor::ActorOwn<ValidatorManagerInterface> ValidatorManagerFactory::create(
 }
 
 void ValidatorManagerImpl::record_collate_query_stats(BlockIdExt block_id, double work_time, double cpu_work_time,
-                                                      CollationStats stats) {
+                                                      td::optional<CollationStats> stats) {
+  if (!stats) {
+    ++(block_id.is_masterchain() ? total_collated_blocks_master_error_ : total_collated_blocks_shard_error_);
+    return;
+  }
   auto &record = new_block_stats_record(block_id);
   record.collator_work_time_ = work_time;
   record.collator_cpu_work_time_ = cpu_work_time;
-  record.collator_stats_ = std::move(stats);
+  record.collator_stats_ = std::move(stats.value());
+  ++(block_id.is_masterchain() ? total_collated_blocks_master_ok_ : total_collated_blocks_shard_ok_);
 }
 
-void ValidatorManagerImpl::record_validate_query_stats(BlockIdExt block_id, double work_time, double cpu_work_time) {
+void ValidatorManagerImpl::record_validate_query_stats(BlockIdExt block_id, double work_time, double cpu_work_time,
+                                                       bool success) {
   auto &record = new_block_stats_record(block_id);
   record.validator_work_time_ = work_time;
   record.validator_cpu_work_time_ = cpu_work_time;
+  if (success) {
+    ++(block_id.is_masterchain() ? total_validated_blocks_master_ok_ : total_validated_blocks_shard_ok_);
+  } else {
+    ++(block_id.is_masterchain() ? total_validated_blocks_master_error_ : total_validated_blocks_shard_error_);
+  }
 }
 
 ValidatorManagerImpl::RecordedBlockStats &ValidatorManagerImpl::new_block_stats_record(BlockIdExt block_id) {
@@ -3377,6 +3434,16 @@ ValidatorManagerImpl::RecordedBlockStats &ValidatorManagerImpl::new_block_stats_
   return recorded_block_stats_[block_id];
 }
 
+void ValidatorManagerImpl::register_stats_provider(
+    td::uint64 idx, std::string prefix,
+    std::function<void(td::Promise<std::vector<std::pair<std::string, std::string>>>)> callback) {
+  stats_providers_[idx] = {std::move(prefix), std::move(callback)};
+}
+
+void ValidatorManagerImpl::unregister_stats_provider(td::uint64 idx) {
+  stats_providers_.erase(idx);
+}
+
 size_t ValidatorManagerImpl::CheckedExtMsgCounter::get_msg_count(WorkchainId wc, StdSmcAddress addr) {
   before_query();
   auto it1 = counter_cur_.find({wc, addr});
diff --git a/validator/manager.hpp b/validator/manager.hpp
index 519cab12a..418deb350 100644
--- a/validator/manager.hpp
+++ b/validator/manager.hpp
@@ -655,8 +655,9 @@ class ValidatorManagerImpl : public ValidatorManager {
       td::optional<ShardIdFull> shard,
       td::Promise<tl_object_ptr<lite_api::liteServer_nonfinal_validatorGroups>> promise) override;
 
-  void add_lite_query_stats(int lite_query_id) override {
+  void add_lite_query_stats(int lite_query_id, bool success) override {
     ++ls_stats_[lite_query_id];
+    ++(success ? total_ls_queries_ok_ : total_ls_queries_error_)[lite_query_id];
   }
 
  private:
@@ -733,7 +734,7 @@ class ValidatorManagerImpl : public ValidatorManager {
 
   void got_persistent_state_descriptions(std::vector<td::Ref<PersistentStateDescription>> descs);
   void add_persistent_state_description_impl(td::Ref<PersistentStateDescription> desc);
-  td::Ref<PersistentStateDescription> get_block_persistent_state(BlockIdExt block_id);
+  td::Ref<PersistentStateDescription> get_block_persistent_state_to_download(BlockIdExt block_id);
 
  private:
   bool need_monitor(ShardIdFull shard) const {
@@ -747,6 +748,16 @@ class ValidatorManagerImpl : public ValidatorManager {
   std::map<int, td::uint32> ls_stats_;  // lite_api ID -> count, 0 for unknown
   td::uint32 ls_stats_check_ext_messages_{0};
 
+  UnixTime started_at_ = (UnixTime)td::Clocks::system();
+  std::map<int, td::uint64> total_ls_queries_ok_, total_ls_queries_error_;  // lite_api ID -> count, 0 for unknown
+  td::uint64 total_check_ext_messages_ok_{0}, total_check_ext_messages_error_{0};
+  td::uint64 total_collated_blocks_master_ok_{0}, total_collated_blocks_master_error_{0};
+  td::uint64 total_validated_blocks_master_ok_{0}, total_validated_blocks_master_error_{0};
+  td::uint64 total_collated_blocks_shard_ok_{0}, total_collated_blocks_shard_error_{0};
+  td::uint64 total_validated_blocks_shard_ok_{0}, total_validated_blocks_shard_error_{0};
+
+  size_t active_validator_groups_master_{0}, active_validator_groups_shard_{0};
+
   td::actor::ActorOwn<CandidatesBuffer> candidates_buffer_;
 
   struct RecordedBlockStats {
@@ -760,16 +771,25 @@ class ValidatorManagerImpl : public ValidatorManager {
   std::queue<BlockIdExt> recorded_block_stats_lru_;
 
   void record_collate_query_stats(BlockIdExt block_id, double work_time, double cpu_work_time,
-                                  CollationStats stats) override;
-  void record_validate_query_stats(BlockIdExt block_id, double work_time, double cpu_work_time) override;
+                                  td::optional<CollationStats> stats) override;
+  void record_validate_query_stats(BlockIdExt block_id, double work_time, double cpu_work_time, bool success) override;
   RecordedBlockStats &new_block_stats_record(BlockIdExt block_id);
 
+  void register_stats_provider(
+      td::uint64 idx, std::string prefix,
+      std::function<void(td::Promise<std::vector<std::pair<std::string, std::string>>>)> callback) override;
+  void unregister_stats_provider(td::uint64 idx) override;
+
   std::map<PublicKeyHash, td::actor::ActorOwn<ValidatorTelemetry>> validator_telemetry_;
 
   void init_validator_telemetry();
 
   std::map<BlockSeqno, td::Ref<PersistentStateDescription>> persistent_state_descriptions_;
   std::map<BlockIdExt, td::Ref<PersistentStateDescription>> persistent_state_blocks_;
+
+  std::map<td::uint64,
+           std::pair<std::string, std::function<void(td::Promise<std::vector<std::pair<std::string, std::string>>>)>>>
+      stats_providers_;
 };
 
 }  // namespace validator
diff --git a/validator/net/download-state.cpp b/validator/net/download-state.cpp
index 2b373ef37..6735a2b5f 100644
--- a/validator/net/download-state.cpp
+++ b/validator/net/download-state.cpp
@@ -70,6 +70,7 @@ void DownloadState::finish_query() {
 }
 
 void DownloadState::start_up() {
+  status_ = ProcessStatus(validator_manager_, "process.download_state_net");
   alarm_timestamp() = timeout_;
 
   td::actor::send_closure(validator_manager_, &ValidatorManagerInterface::get_persistent_state, block_id_,
@@ -190,6 +191,7 @@ void DownloadState::got_block_state_description(td::BufferSlice data) {
                                       td::Timestamp::in(3.0), std::move(P));
             }
           }));
+  status_.set_status(PSTRING() << block_id_.id.to_str() << " : 0 bytes, 0B/s");
 }
 
 void DownloadState::got_block_state_part(td::BufferSlice data, td::uint32 requested_size) {
@@ -198,14 +200,18 @@ void DownloadState::got_block_state_part(td::BufferSlice data, td::uint32 reques
   parts_.push_back(std::move(data));
 
   double elapsed = prev_logged_timer_.elapsed();
-  if (elapsed > 10.0) {
+  if (elapsed > 5.0) {
     prev_logged_timer_ = td::Timer();
+    auto speed = (td::uint64)((double)(sum_ - prev_logged_sum_) / elapsed);
     LOG(WARNING) << "downloading state " << block_id_.to_str() << ": " << td::format::as_size(sum_) << " ("
-                 << td::format::as_size((td::uint64)(double(sum_ - prev_logged_sum_) / elapsed)) << "/s)";
+                 << td::format::as_size(speed) << "/s)";
+    status_.set_status(PSTRING() << block_id_.id.to_str() << " : " << sum_ << " bytes, " << td::format::as_size(speed)
+                                 << "/s");
     prev_logged_sum_ = sum_;
   }
 
   if (last_part) {
+    status_.set_status(PSTRING() << block_id_.id.to_str() << " : " << sum_ << " bytes, finishing");
     td::BufferSlice res{td::narrow_cast<std::size_t>(sum_)};
     auto S = res.as_slice();
     for (auto &p : parts_) {
diff --git a/validator/net/download-state.hpp b/validator/net/download-state.hpp
index 19c44beb3..470c54318 100644
--- a/validator/net/download-state.hpp
+++ b/validator/net/download-state.hpp
@@ -23,6 +23,8 @@
 #include "validator/validator.h"
 #include "adnl/adnl-ext-client.h"
 
+#include <stats-provider.h>
+
 namespace ton {
 
 namespace validator {
@@ -75,6 +77,8 @@ class DownloadState : public td::actor::Actor {
 
   td::uint64 prev_logged_sum_ = 0;
   td::Timer prev_logged_timer_;
+
+  ProcessStatus status_;
 };
 
 }  // namespace fullnode
diff --git a/validator/state-serializer.cpp b/validator/state-serializer.cpp
index b693232b4..bc3d7b5e0 100644
--- a/validator/state-serializer.cpp
+++ b/validator/state-serializer.cpp
@@ -58,6 +58,12 @@ void AsyncStateSerializer::got_self_state(AsyncSerializerState state) {
     });
     td::actor::send_closure(manager_, &ValidatorManager::get_block_handle, last_block_id_, true, std::move(P));
   }
+
+  inited_block_id_ = true;
+  for (auto& promise : wait_init_block_id_) {
+    promise.set_value(td::Unit());
+  }
+  wait_init_block_id_.clear();
 }
 
 void AsyncStateSerializer::got_init_handle(BlockHandle handle) {
@@ -186,6 +192,9 @@ void AsyncStateSerializer::next_iteration() {
               td::actor::send_closure(SelfId, &AsyncStateSerializer::request_previous_state_files);
             },
             td::Timestamp::in(delay));
+        current_status_ = PSTRING() << "delay before serializing seqno=" << masterchain_handle_->id().seqno() << " "
+                                    << (int)delay << "s";
+        current_status_ts_ = td::Timestamp::now();
         return;
       }
       if (next_idx_ < shards_.size()) {
@@ -379,9 +388,14 @@ void AsyncStateSerializer::got_masterchain_state(td::Ref<MasterchainState> state
 
   td::actor::send_closure(manager_, &ValidatorManager::store_persistent_state_file_gen, masterchain_handle_->id(),
                           masterchain_handle_->id(), write_data, std::move(P));
+
+  current_status_ = PSTRING() << "serializing masterchain state " << state->get_block_id().id.to_str();
+  current_status_ts_ = td::Timestamp::now();
 }
 
 void AsyncStateSerializer::stored_masterchain_state() {
+  current_status_ = "pending";
+  current_status_ts_ = {};
   LOG(ERROR) << "finished serializing masterchain state " << masterchain_handle_->id().id.to_str();
   running_ = false;
   next_iteration();
@@ -444,9 +458,14 @@ void AsyncStateSerializer::got_shard_state(BlockHandle handle, td::Ref<ShardStat
   });
   td::actor::send_closure(manager_, &ValidatorManager::store_persistent_state_file_gen, handle->id(),
                           masterchain_handle_->id(), write_data, std::move(P));
+  current_status_ = PSTRING() << "serializing shard state " << next_idx_ << "/" << shards_.size() << " "
+                              << state->get_block_id().id.to_str();
+  current_status_ts_ = td::Timestamp::now();
 }
 
 void AsyncStateSerializer::fail_handler(td::Status reason) {
+  current_status_ = PSTRING() << "pending, " << reason;
+  current_status_ts_ = {};
   VLOG(VALIDATOR_NOTICE) << "failure: " << reason;
   attempt_++;
   delay_action(
@@ -460,6 +479,8 @@ void AsyncStateSerializer::fail_handler_cont() {
 }
 
 void AsyncStateSerializer::success_handler() {
+  current_status_ = "pending";
+  current_status_ts_ = {};
   running_ = false;
   next_iteration();
 }
@@ -478,6 +499,29 @@ void AsyncStateSerializer::auto_disable_serializer(bool disabled) {
   }
 }
 
+void AsyncStateSerializer::prepare_stats(td::Promise<std::vector<std::pair<std::string, std::string>>> promise) {
+  if (!inited_block_id_) {
+    wait_init_block_id_.push_back(
+        [SelfId = actor_id(this), promise = std::move(promise)](td::Result<td::Unit> R) mutable {
+          TRY_STATUS_PROMISE(promise, R.move_as_status());
+          td::actor::send_closure(SelfId, &AsyncStateSerializer::prepare_stats, std::move(promise));
+        });
+    return;
+  }
+  std::vector<std::pair<std::string, std::string>> vec;
+  vec.emplace_back("stateserializermasterchainseqno", td::to_string(last_block_id_.seqno()));
+  td::StringBuilder sb;
+  sb << current_status_;
+  if (current_status_ts_) {
+    sb << " (started " << (int)(td::Timestamp::now() - current_status_ts_) << "s ago)";
+  }
+  if (!opts_->get_state_serializer_enabled() || auto_disabled_) {
+    sb << " (disabled)";
+  }
+  vec.emplace_back("stateserializerstatus", sb.as_cslice().str());
+  promise.set_result(std::move(vec));
+}
+
 bool AsyncStateSerializer::need_serialize(BlockHandle handle) {
   if (handle->id().id.seqno == 0 || !handle->is_key_block()) {
     return false;
diff --git a/validator/state-serializer.hpp b/validator/state-serializer.hpp
index 1e7f5c9ca..406ac350a 100644
--- a/validator/state-serializer.hpp
+++ b/validator/state-serializer.hpp
@@ -36,6 +36,9 @@ class AsyncStateSerializer : public td::actor::Actor {
   UnixTime last_key_block_ts_ = 0;
   bool saved_to_db_ = true;
 
+  bool inited_block_id_ = false;
+  std::vector<td::Promise<td::Unit>> wait_init_block_id_;
+
   td::Ref<ValidatorManagerOptions> opts_;
   bool auto_disabled_ = false;
   td::CancellationTokenSource cancellation_token_source_;
@@ -95,6 +98,8 @@ class AsyncStateSerializer : public td::actor::Actor {
     promise.set_result(last_block_id_.id.seqno);
   }
 
+  void prepare_stats(td::Promise<std::vector<std::pair<std::string, std::string>>> promise);
+
   void update_last_known_key_block_ts(UnixTime ts) {
     last_known_key_block_ts_ = std::max(last_known_key_block_ts_, ts);
   }
@@ -111,6 +116,9 @@ class AsyncStateSerializer : public td::actor::Actor {
 
   void update_options(td::Ref<ValidatorManagerOptions> opts);
   void auto_disable_serializer(bool disabled);
+
+  std::string current_status_ = "pending";
+  td::Timestamp current_status_ts_ = td::Timestamp::never();
 };
 
 }  // namespace validator
diff --git a/validator/stats-provider.h b/validator/stats-provider.h
new file mode 100644
index 000000000..e0a7f5650
--- /dev/null
+++ b/validator/stats-provider.h
@@ -0,0 +1,105 @@
+/*
+    This file is part of TON Blockchain Library.
+
+    TON Blockchain Library is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    TON Blockchain Library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with TON Blockchain Library.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#pragma once
+
+#include "validator.h"
+#include "common/AtomicRef.h"
+
+#include <atomic>
+
+namespace ton {
+
+namespace validator {
+
+class StatsProvider {
+ public:
+  StatsProvider() = default;
+  StatsProvider(td::actor::ActorId<ValidatorManagerInterface> manager, std::string prefix,
+                std::function<void(td::Promise<std::vector<std::pair<std::string, std::string>>>)> callback)
+      : inited_(true), manager_(std::move(manager)) {
+    static std::atomic<td::uint64> cur_idx{0};
+    idx_ = cur_idx.fetch_add(1);
+    td::actor::send_closure(manager_, &ValidatorManagerInterface::register_stats_provider, idx_, std::move(prefix),
+                            std::move(callback));
+  }
+  StatsProvider(const StatsProvider&) = delete;
+  StatsProvider(StatsProvider&& other) noexcept
+      : inited_(other.inited_), idx_(other.idx_), manager_(std::move(other.manager_)) {
+    other.inited_ = false;
+  }
+  ~StatsProvider() {
+    if (inited_) {
+      td::actor::send_closure(manager_, &ValidatorManagerInterface::unregister_stats_provider, idx_);
+    }
+  }
+
+  StatsProvider& operator=(const StatsProvider&) = delete;
+  StatsProvider& operator=(StatsProvider&& other) noexcept {
+    if (this != &other) {
+      inited_ = other.inited_;
+      idx_ = other.idx_;
+      manager_ = std::move(other.manager_);
+      other.inited_ = false;
+    }
+    return *this;
+  }
+
+  bool inited() const {
+    return inited_;
+  }
+
+ private:
+  bool inited_ = false;
+  td::uint64 idx_ = 0;
+  td::actor::ActorId<ValidatorManagerInterface> manager_;
+};
+
+class ProcessStatus {
+ public:
+  ProcessStatus() = default;
+  ProcessStatus(td::actor::ActorId<ValidatorManagerInterface> manager, std::string name)
+      : stats_provider_(std::move(manager), std::move(name), [value = value_](auto promise) {
+        auto status = value->load();
+        if (status.is_null()) {
+          promise.set_error(td::Status::Error("empty"));
+          return;
+        }
+        std::vector<std::pair<std::string, std::string>> vec;
+        vec.emplace_back("", *status);
+        promise.set_value(std::move(vec));
+      }) {
+  }
+  ProcessStatus(const ProcessStatus&) = delete;
+  ProcessStatus(ProcessStatus&& other) noexcept = default;
+  ProcessStatus& operator=(const ProcessStatus&) = delete;
+  ProcessStatus& operator=(ProcessStatus&& other) noexcept = default;
+
+  void set_status(std::string s) {
+    if (!value_) {
+      return;
+    }
+    value_->store(td::Ref<td::Cnt<std::string>>(true, std::move(s)));
+  }
+
+ private:
+  std::shared_ptr<td::AtomicRef<td::Cnt<std::string>>> value_ = std::make_shared<td::AtomicRef<td::Cnt<std::string>>>();
+  StatsProvider stats_provider_;
+};
+
+}  // namespace validator
+
+}  // namespace ton
diff --git a/validator/validator-group.cpp b/validator/validator-group.cpp
index 1817180db..110ccd813 100644
--- a/validator/validator-group.cpp
+++ b/validator/validator-group.cpp
@@ -373,6 +373,7 @@ void ValidatorGroup::create_session() {
   }
   CHECK(found);
 
+  config_.catchain_opts.broadcast_speed_multiplier = opts_->get_catchain_broadcast_speed_multiplier();
   if (!config_.new_catchain_ids) {
     session_ = validatorsession::ValidatorSession::create(session_id_, config_, local_id_, std::move(vec),
                                                           make_validator_session_callback(), keyring_, adnl_, rldp_,
diff --git a/validator/validator-options.hpp b/validator/validator-options.hpp
index e958d8864..ace6b1066 100644
--- a/validator/validator-options.hpp
+++ b/validator/validator-options.hpp
@@ -154,6 +154,9 @@ struct ValidatorManagerOptionsImpl : public ValidatorManagerOptions {
   bool get_fast_state_serializer_enabled() const override {
     return fast_state_serializer_enabled_;
   }
+  double get_catchain_broadcast_speed_multiplier() const override {
+    return catchain_broadcast_speed_multipliers_;
+  }
 
   void set_zero_block_id(BlockIdExt block_id) override {
     zero_block_id_ = block_id;
@@ -249,6 +252,9 @@ struct ValidatorManagerOptionsImpl : public ValidatorManagerOptions {
   void set_fast_state_serializer_enabled(bool value) override {
     fast_state_serializer_enabled_ = value;
   }
+  void set_catchain_broadcast_speed_multiplier(double value) override {
+    catchain_broadcast_speed_multipliers_ = value;
+  }
 
   ValidatorManagerOptionsImpl *make_copy() const override {
     return new ValidatorManagerOptionsImpl(*this);
@@ -302,6 +308,7 @@ struct ValidatorManagerOptionsImpl : public ValidatorManagerOptions {
   bool state_serializer_enabled_ = true;
   td::Ref<CollatorOptions> collator_options_{true};
   bool fast_state_serializer_enabled_ = false;
+  double catchain_broadcast_speed_multipliers_;
 };
 
 }  // namespace validator
diff --git a/validator/validator.h b/validator/validator.h
index 73065aa98..5d6c0173c 100644
--- a/validator/validator.h
+++ b/validator/validator.h
@@ -20,6 +20,7 @@
 
 #include <vector>
 #include <deque>
+#include <functional>
 
 #include "td/actor/actor.h"
 
@@ -115,6 +116,7 @@ struct ValidatorManagerOptions : public td::CntObject {
   virtual bool get_state_serializer_enabled() const = 0;
   virtual td::Ref<CollatorOptions> get_collator_options() const = 0;
   virtual bool get_fast_state_serializer_enabled() const = 0;
+  virtual double get_catchain_broadcast_speed_multiplier() const = 0;
 
   virtual void set_zero_block_id(BlockIdExt block_id) = 0;
   virtual void set_init_block_id(BlockIdExt block_id) = 0;
@@ -147,6 +149,7 @@ struct ValidatorManagerOptions : public td::CntObject {
   virtual void set_state_serializer_enabled(bool value) = 0;
   virtual void set_collator_options(td::Ref<CollatorOptions> value) = 0;
   virtual void set_fast_state_serializer_enabled(bool value) = 0;
+  virtual void set_catchain_broadcast_speed_multiplier(double value) = 0;
 
   static td::Ref<ValidatorManagerOptions> create(
       BlockIdExt zero_block_id, BlockIdExt init_block_id,
@@ -292,6 +295,13 @@ class ValidatorManagerInterface : public td::actor::Actor {
   virtual void get_out_msg_queue_size(BlockIdExt block_id, td::Promise<td::uint64> promise) = 0;
 
   virtual void update_options(td::Ref<ValidatorManagerOptions> opts) = 0;
+
+  virtual void register_stats_provider(
+      td::uint64 idx, std::string prefix,
+      std::function<void(td::Promise<std::vector<std::pair<std::string, std::string>>>)> callback) {
+  }
+  virtual void unregister_stats_provider(td::uint64 idx) {
+  }
 };
 
 }  // namespace validator