diff --git a/include/boost/config/stdlib/libcomo.hpp b/include/boost/config/stdlib/libcomo.hpp
index 72029c5c..dbbdc2fc 100644
--- a/include/boost/config/stdlib/libcomo.hpp
+++ b/include/boost/config/stdlib/libcomo.hpp
@@ -15,8 +15,9 @@
 #endif
 
 //
-// std::streambuf<wchar_t> is non-standard:
-//
+// std::streambuf<wchar_t> is non-standard
+// NOTE: versions of libcomo prior to beta28 have octal version numbering,
+// e.g. version 25 is 21 (dec)
 #if __LIBCOMO_VERSION__ <= 22
 #  define BOOST_NO_STD_WSTREAMBUF
 #endif