diff --git a/docs/3.0-upgrade-notes.md b/docs/3.0-upgrade-notes.md
index 98494fdd..3027255c 100644
--- a/docs/3.0-upgrade-notes.md
+++ b/docs/3.0-upgrade-notes.md
@@ -1,5 +1,9 @@
 # 3.0 Upgrade Notes
 
+## elm.json
+
+- Add dependency `"lamdera/codecs": "1.0.0"`
+
 ## File Structure
 
 - `rm -rf .elm-pages`