diff --git a/Project.toml b/Project.toml
index 3cac18e..fda49aa 100644
--- a/Project.toml
+++ b/Project.toml
@@ -4,7 +4,7 @@ authors  = ["ScottPJones <scottjones@alum.mit.edu>"]
 keywords = ["Strings"]
 license  = "MIT"
 uuid     = "e79e7a6a-7bb1-5a4d-9d64-da657b06f53a"
-version  = "0.1.10"
+version  = "0.1.11"
 
 [deps]
 Pkg     = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
diff --git a/REQUIRE b/REQUIRE
index 0150ff3..2a93f0e 100644
--- a/REQUIRE
+++ b/REQUIRE
@@ -3,4 +3,4 @@ MurmurHash3 0.1.5
 ModuleInterfaceTools 0.1.6
 StrAPI 0.1.8
 CharSetEncodings 0.1.8
-ChrBase 0.1.6
+ChrBase 0.1.7
diff --git a/src/StrBase.jl b/src/StrBase.jl
index 15bdcd0..b3ad859 100644
--- a/src/StrBase.jl
+++ b/src/StrBase.jl
@@ -32,7 +32,7 @@ using ModuleInterfaceTools
              _memcmp, _memcpy, _memset, _fwd_memchr, _rev_memchr,
              empty_string, _calcpnt, _mask_bytes, _allocate,
              MS_UTF8, MS_UTF16, MS_UTF32, MS_SubUTF32, MS_Latin, MS_ByteStr, MS_RawUTF8,
-             _wrap_substr, _empty_sub, 
+             _wrap_substr, _empty_sub,
              AccessType, UInt16_U, UInt32_U, UInt16_S, UInt32_S, UInt16_US, UInt32_US,
              alignedtype, swappedtype, checkkeep, splitarr, __split, __rsplit, __replace
 
diff --git a/src/casefold.jl b/src/casefold.jl
index aefbe95..40c5ee2 100644
--- a/src/casefold.jl
+++ b/src/casefold.jl
@@ -359,7 +359,7 @@ function uppercase(str::MaybeSub{S}) where {C<:Union{UCS2_CSEs,UTF32_CSEs},S<:St
         pnt = beg = pointer(str)
         fin = beg + sizeof(str)
         while pnt < fin
-            _can_upper_ch(get_codeunit(pnt)) && return _upper(C, beg, pnt-beg, ncodeunits(str))
+            _wide_lower_ch(get_codeunit(pnt)) && return _upper(C, beg, pnt-beg, ncodeunits(str))
             pnt += sizeof(CU)
         end
         str
diff --git a/src/utf16case.jl b/src/utf16case.jl
index 5e09278..fa76844 100644
--- a/src/utf16case.jl
+++ b/src/utf16case.jl
@@ -97,7 +97,7 @@ function uppercase(str::UTF16Str)
             prv = pnt
             (ch > 0xd7ff # May be surrogate pair
              ? _islower_u(ch > 0xdfff ? ch%UInt32 : get_supplementary(ch, get_codeunit(pnt += 2)))
-             : _can_upper_ch(ch)) &&
+             : _wide_lower_ch(ch)) &&
                  return _upper(UTF16Str, beg, prv-beg, ncodeunits(str))
             pnt += 2
         end
diff --git a/src/utf8case.jl b/src/utf8case.jl
index 1d532d9..b191f51 100644
--- a/src/utf8case.jl
+++ b/src/utf8case.jl
@@ -91,18 +91,22 @@ function _upper_utf8(beg, off, len)
             out += 1
         elseif ch < 0xc4
             ch = (ch << 6) | (get_codeunit(pnt += 1) & 0x3f)
-            if _can_upper_l(ch)
-                c16 = (ch - 0x20)%UInt16
-            elseif ch == 0xb5
-                c16 = 0x39c
-            elseif ch == 0xff
-                c16 = 0x178
-            elseif !V6_COMPAT && ch == 0xdf
-                c16 = 0x1e9e
+            if !V6_COMPAT && ch == 0xdf
+                # Increasing from 2 to 3 bytes, check to see if we need to resize
+                diff = (outend - out - 3) - (fin - pnt - 1)
+                if diff < 0
+                    outend -= diff
+                    resize!(buf, outend - out)
+                    out = pointer(buf)
+                    outend = out + sizeof(buf)
+                end
+                out = output_utf8_3byte!(out, 0x1e9e)
             else
-                c16 = ch%UInt16
+                out = output_utf8_2byte!(out, _can_upper_l(ch) ? (ch - 0x20)%UInt16
+                                              : ch == 0xb5 ? 0x39c
+                                              : ch == 0xff ? 0x178
+                                              : ch%UInt16)
             end
-            out = output_utf8_2byte!(out, c16)
         elseif ch < 0xe0
             # 2 byte
             c16 = get_utf8_2byte(pnt += 1, ch)
diff --git a/test/basic.jl b/test/basic.jl
index c1bda75..f9043f8 100644
--- a/test/basic.jl
+++ b/test/basic.jl
@@ -34,6 +34,28 @@ end
     end
 end
 
+@testset "casefold string" begin
+    for ST in (ASCIIStr, LatinStr, UCS2Str, UTF32Str, UTF8Str, UTF16Str)
+        C = eltype(ST)
+        tm = typemax(C)
+        for c = 0:Int(tm)
+            # Skip surrogates
+            0xd800 <= c < 0xe000 && continue
+            ch = C(c)
+            # Check to make sure this character would still fit uppercased
+            cu = uppercase(ch)
+            cu > tm && continue
+            for str in ("$ch test Beg", "test End $ch", "test $ch Mid", "$ch")
+                cvtstr = convert(ST, str)
+                @test uppercase(str) == uppercase(cvtstr)
+                @test lowercase(str) == lowercase(cvtstr)
+                @test titlecase(str) == titlecase(cvtstr)
+                @test uppercase_first(str) == uppercase_first(cvtstr)
+            end
+        end
+    end
+end
+
 @testset "{starts,ends}_with" begin
     for (ST, type_list) in compat_types, CT in type_list, str in test_strings_base[CT]
         cvtstr = convert(ST, str)