diff -r 691131ce4641 -r c256bba593f3 NEWS
--- a/NEWS	Sat Nov 27 10:28:48 2021 +0100
+++ b/NEWS	Sat Nov 27 10:46:57 2021 +0100
@@ -26,6 +26,7 @@
   - Added predicate multp equivalent to set mult. Reuse name previously
     used for what is now called multp_code. Minor INCOMPATIBILITY.
   - Lifted multiple lemmas from mult to multp.
+  - Redefined less_multiset to be based on multp. INCOMPATIBILITY.
 
 
 New in Isabelle2021-1 (December 2021)