diff --git a/WHATSNEW b/WHATSNEW
index a2ee48782..ee836c25d 100644
--- a/WHATSNEW
+++ b/WHATSNEW
@@ -92,6 +92,9 @@ Fixed bugs:
 
 * Targets with identical name work in imported project. Bugzilla Report 34566.
 
+* DemuxOutputStream now uses a WeakHashMap to store the thread-stream mapping,
+  to avoid holding on to thread references after they terminate. 
+
 Other changes:
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