diff -r 0b1b7465f2ef -r c2b38181b7f1 NEWS
--- a/NEWS	Wed Mar 16 21:45:04 2016 +0100
+++ b/NEWS	Wed Mar 16 22:04:38 2016 +0100
@@ -281,6 +281,9 @@
 
 * SML/NJ and old versions of Poly/ML are no longer supported.
 
+* Poly/ML heaps now follow the hierarchy of sessions, and thus require
+much less disk space.
+
 
 
 New in Isabelle2016 (February 2016)