Simplify upgrade instructions

wiki/src/contribute/how/documentation/release_notes/template.mdwn

@@ -69,10 +69,7 @@ See the list of [[long-standing issues|support/known_issues]].
 
 ## To upgrade your Tails USB stick and keep your persistent storage
 
-- Automatic upgrades are available from $VERSION-2, $VERSION-1, and $VERSION-1~rc1 to $VERSION.
-
-  XXX: In theory, there should be automatic upgrades available from
-       4.2 onwards.
+- Automatic upgrades are available from Tails 4.2 or later to $VERSION.
 
 - If you cannot do an automatic upgrade or if Tails fails to start after an
   automatic upgrade, please try to do a [[manual upgrade|doc/upgrade/#manual]].