diff --git a/doc/Changelog b/doc/Changelog
index a225c3181..8a420d770 100644
--- a/doc/Changelog
+++ b/doc/Changelog
@@ -3,6 +3,7 @@
 	  build. The current code repository continues with version 1.13.3.
 	- Add test tool readzone to .gitignore.
 	- Merge #521: Update mini_event.c.
+	- Merge #523: fix: free() call more than once with the same pointer.
 
 5 August 2021: Wouter
 	- Tag for 1.13.2rc1 release.