diff --git a/source/birchwood/protocol/constants.d b/source/birchwood/protocol/constants.d
index 5ac148d..b01a5e4 100644
--- a/source/birchwood/protocol/constants.d
+++ b/source/birchwood/protocol/constants.d
@@ -158,6 +158,7 @@ public enum ReplyType : ulong
     RPL_CREATED = 003,
     RPL_MYINFO = 004,
     RPL_BOUNCE = 005, // TODO: We care about the key-value pairs here in RPL_BOUNCE
+    ERR_NOCHANMODES = 477,