diff --git a/winsup/cygwin/release/1.7.30 b/winsup/cygwin/release/1.7.30
index 400216469..0bd206a40 100644
--- a/winsup/cygwin/release/1.7.30
+++ b/winsup/cygwin/release/1.7.30
@@ -9,6 +9,10 @@ What's new:
 What changed:
 -------------
 
+- Windows defines the IPV6_TCLASS option, but when using it in setsockopt
+  it returns WSAENOPROTOOPT.  Cygwin now ignores this error condition and
+  returns a fake success to the application, just as with IP_TOS for years.
+
 
 Bug Fixes
 ---------