diff --git a/INSTALL.md b/INSTALL.md
index 501f8017cd..a01b04ae1e 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -17,7 +17,7 @@ NEW or CHANGED MINIMUM dependencies since the last major release are **bold**.
  * **C++17 or higher** (also builds with C++20)
      * The default build mode is C++17. This can be controlled by via the
        CMake configuration flag: `-DCMAKE_CXX_STANDARD=20`, etc.
- * Compilers: **gcc 9.3** - 13.1, **clang 5** - 17, MSVS 2017 - 2019 (**v19.14
+ * Compilers: **gcc 9.3** - 13.1, **clang 5** - 18, MSVS 2017 - 2019 (**v19.14
    and up**), **Intel icc 19+**, Intel OneAPI C++ compiler 2022+.
  * **CMake >= 3.15** (tested through 3.28)
  * **OpenEXR/Imath >= 3.1** (tested through 3.2
diff --git a/src/include/OpenImageIO/detail/fmt.h b/src/include/OpenImageIO/detail/fmt.h
index 4d9456ebdb..74e6fae78c 100644
--- a/src/include/OpenImageIO/detail/fmt.h
+++ b/src/include/OpenImageIO/detail/fmt.h
@@ -48,6 +48,7 @@
 #    define FMT_USE_FLOAT128 0
 #endif
 
+// Suppress certain warnings generated in the fmt headers themselves
 OIIO_PRAGMA_WARNING_PUSH
 #if OIIO_GNUC_VERSION >= 70000
 #    pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
@@ -58,6 +59,9 @@ OIIO_PRAGMA_WARNING_PUSH
 #if OIIO_INTEL_LLVM_COMPILER
 #    pragma GCC diagnostic ignored "-Wtautological-constant-compare"
 #endif
+#if OIIO_CLANG_VERSION >= 180000
+#    pragma clang diagnostic ignored "-Wdeprecated-declarations"
+#endif
 
 #include <OpenImageIO/detail/fmt/format.h>
 #include <OpenImageIO/detail/fmt/ostream.h>
diff --git a/src/libutil/strutil.cpp b/src/libutil/strutil.cpp
index 2ac8f561e9..4c8ded417c 100644
--- a/src/libutil/strutil.cpp
+++ b/src/libutil/strutil.cpp
@@ -3,16 +3,24 @@
 // https://github.com/AcademySoftwareFoundation/OpenImageIO
 
 
+#include <OpenImageIO/platform.h>
+
+// Special dance to disable warnings in the included files related to
+// the deprecation of unicode conversion functions.
+OIIO_PRAGMA_WARNING_PUSH
+OIIO_CLANG_PRAGMA(clang diagnostic ignored "-Wdeprecated-declarations")
+#include <codecvt>
+#include <locale>
+OIIO_PRAGMA_WARNING_POP
+
 #include <algorithm>
 #include <cmath>
-#include <codecvt>
 #include <cstdarg>
 #include <cstdint>
 #include <cstdlib>
 #include <ctime>
 #include <iostream>
 #include <limits>
-#include <locale>
 #include <mutex>
 #include <numeric>
 #include <sstream>
@@ -23,7 +31,6 @@
 #endif
 
 #include <OpenImageIO/dassert.h>
-#include <OpenImageIO/platform.h>
 #include <OpenImageIO/string_view.h>
 #include <OpenImageIO/strutil.h>
 #include <OpenImageIO/thread.h>