Hey everyone,
Recently my team needed to change a MediaWiki message in core, MediaWiki:Welcomecreation. This message was presented to users after they registered, and while the default contents have not changed (except for the header, which now reads "Welcome, $1!", where $1 is the username).
However, any custom content that communities placed in to MediaWiki:Welcomecreation needs to be moved to the new message, MediaWiki:Welcomecreation-msg. We've generated a list of all the wikis that seem to have customized the content.[1]
Apologies for any inconvenience, but changing the message was the cleanest way to change the header text. If you can help get the word out to local admins, that would be a huge help.