diff --git a/src/format.cc b/src/format.cc
index 391d3a24..70d12d6b 100644
--- a/src/format.cc
+++ b/src/format.cc
@@ -26,6 +26,7 @@ template FMT_API auto thousands_sep_impl(locale_ref)
     -> thousands_sep_result<char>;
 template FMT_API auto decimal_point_impl(locale_ref) -> char;
 
+// DEPRECATED!
 template FMT_API void buffer<char>::append(const char*, const char*);
 
 template FMT_API void vformat_to(buffer<char>&, string_view,