diff --git a/RELEASE b/RELEASE
index 9e1b0f51..f2532dfa 100644
--- a/RELEASE
+++ b/RELEASE
@@ -1,6 +1,11 @@
 This file is used to help provide older releases. Please download the
 attached .tar.gz file to get the particular release.
 
+----
+MacSim v2.1.1
+
+Trace format has been updated.
+
 ----
 MacSim v2.1.0