diff --git a/upgrade.txt b/upgrade.txt
index ad26a714e..809b24292 100644
--- a/upgrade.txt
+++ b/upgrade.txt
@@ -7,6 +7,8 @@ information provided here is intended especially for developers.
 - --addon-messages-* CSS3 variables have been renamed to --core-messages-*
 - The database constants in CoreSite (WS_CACHE_TABLE, CONFIG_TABLE, LAST_VIEWED_TABLE) and the DBRecord types have been moved to src/core/services/database.
 - The component <core-block> will no longer detect changes of properties inside the extraData object, it will only detect changes if the object itself changes.
+- CSS variable declarations have been moved to the `html` selector instead of using `body` and `:root`.
+- The second argument of `CoreTextUtilsProvider.cleanTags` has been converted into an object with boolean flags.
 
 === 4.0.0 ===