diff --git a/CHANGES/v2.4.md b/CHANGES/v2.4.md
index 13c07a5b46a310c48baed82d8edc8a19c3241bf6..1c69af7bd2e49e070ca51c0baaed0b815ad43594 100644
--- a/CHANGES/v2.4.md
+++ b/CHANGES/v2.4.md
@@ -209,6 +209,7 @@ For users:
   - GROMACS patch for gromacs-2018.4.
   - Fixed a bug in CS2BACKBONE when using more than 2 chains
   - Fixed a threadsafety issue using forces on histograms
+  - Fixed error message suggesting wrong actions (see \issue{421}).
 
 For developers:
   - All fixed done in version 2.3.8