diff --git a/CHANGES.md b/CHANGES.md
index 119cd55..b793fa8 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -14,6 +14,7 @@ Note - All hash comments refer to the issue number. Eg. #169 refers to https://g
 ### Fixed
 - Managers are now able to download their students' certificates (#412).
 - Users being able to view the certificate before the required time set (#403).
+- Fixed the issue with displaying PDF when debugging is ON (#420).
 
 ## [3.8.5] - 2020-11-26