diff --git a/policies/coding-style.md b/policies/coding-style.md
index 89d1958..afa1cda 100644
--- a/policies/coding-style.md
+++ b/policies/coding-style.md
@@ -705,10 +705,11 @@ it portable enough to meet our multi-platform support goals.
 
 ## Chapter 14: Portability
 
-To maximise portability the version of C defined in ISO/IEC 9899:1990
-should be used. This is more commonly referred to as C90. ISO/IEC 9899:1999
-(also known as C99) is not supported on some platforms that OpenSSL is
-used on and therefore should be avoided.
+To maximise portability the version of C defined in ISO/IEC 9899:1999
+should be used. This is more commonly referred to as C99. C99 can be
+used on code targeting 3.6 and newer branches. Code which is intended
+to be backported to 3.5 and earlier branches should use
+ISO/IEC 9899:1990 (a.k.a. C90).
 
 ## Chapter 15: Expressions