diff --git a/src/util/cmdline.h b/src/util/cmdline.h
index 1d11496fd54..4c891137783 100644
--- a/src/util/cmdline.h
+++ b/src/util/cmdline.h
@@ -105,8 +105,8 @@ class cmdlinet
   {
     explicit option_namest(const cmdlinet &command_line);
     struct option_names_iteratort
-      : public std::iterator<std::forward_iterator_tag, std::string>
     {
+      using iterator_category = std::forward_iterator_tag;
       option_names_iteratort() = default;
       explicit option_names_iteratort(
         const cmdlinet *command_line,
diff --git a/src/util/dense_integer_map.h b/src/util/dense_integer_map.h
index 6d8830e9701..6e2c0bc02d4 100644
--- a/src/util/dense_integer_map.h
+++ b/src/util/dense_integer_map.h
@@ -116,8 +116,8 @@ class dense_integer_mapt
   // operator++ that skips unset values.
   template <class UnderlyingIterator, class UnderlyingValue>
   class iterator_templatet
-    : public std::iterator<std::forward_iterator_tag, UnderlyingValue>
   {
+    using iterator_category = std::forward_iterator_tag;
     // Type of the std::iterator support class we inherit
     typedef std::iterator<std::forward_iterator_tag, UnderlyingValue>
       base_typet;