diff --git a/CHANGES.txt b/CHANGES.txt
index 6aa9a2461..5b4f9f5eb 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,5 +1,6 @@
 Changelog for Shake (* = breaking change)
 
+    #678, fix serious bug in writeFile' - it could delete an unrelated file
 0.18, released 2019-05-14
 *   Make files copied to the shared cache read-only
     Delete files before writing, giving symlink/readonly safety