diff --git a/RELEASE b/RELEASE
index c511586a..dee52cb7 100644
--- a/RELEASE
+++ b/RELEASE
@@ -1,5 +1,43 @@
 This file is used to help provide older releases. Please download the attached
 .tar.gz file to get the particular release.
+----
+MacSim v2.0.0
+
+There are several major changes made since last release. (The svn repository
+already has the latest version.)
+
+  1. MacSim's Trace Format has been changed along with the trace
+     configuration file format. For verification purposes, a few
+     sample traces conforming to the new trace file format are
+     included in this release. For your convenience, more x86 sample
+     traces from spec2006 will also be provided.
+
+     o To make sure your installation is complete (./build.py), please
+       go check using $MACSIM_ROOT/bin/macsim binary. It searches for
+       newly built executable and runs traces listed in
+       trace_file_list to completion.
+
+     o Please download sample traces provided in googlecode page and
+       extract them under $MACSIM_ROOT/trace/ directory. You may need
+       to modify trace_file_list to run more traces other than the
+       included ones.
+
+  2. MacSim is now compatible with Mac OS X.
+
+     o We resolved a few compilation issues that arises with Mac
+       environment.
+
+     o Please note that only g++-4.7 is fully tested and other
+       versions of compilers are not yet fully supported.
+
+  3. Added SST-3.0.0 compatibility
+
+     o There have been a lot of changes made to SST framework (The
+       Structural Simulation Toolkit developed by Sandia National
+       Laboratory) since its last release. We have made a transition
+       from an older version of SST APIs to a newer version to make it
+       compatible with SST-3.0.0.
+
 ----
 MacSim v1.2.0