diff --git a/doc/release-notes/teachpack/HISTORY.txt b/doc/release-notes/teachpack/HISTORY.txt
index 237bd8cf90..d883e3aa67 100644
--- a/doc/release-notes/teachpack/HISTORY.txt
+++ b/doc/release-notes/teachpack/HISTORY.txt
@@ -2,6 +2,8 @@
 Version 5.2				  [Mon Apr 25 11:07:14 EDT 2011]
 
 * tiny bug fix in registration process for universe 
+  implies incompatibility of protocols between 5.1 programs and 
+  predecessors
 
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 Version 5.1				  [Tue Feb  8 13:05:17 EST 2011]