English #Wikipedia will migrate to the new vector skin on Thursday 05:00 UTC. There are no fixed plans yet, but it will take something like two more weeks before the other Wikipedias and other projects will migrate.
This indicates that it is best to to finish localising the usability software for all the other languages in the next two weeks. Please check at translatewiki.net what still needs to be done for your language.
Once the software is integrated in the MediaWiki core, it will change the content of the "most used" messages. They are essential for helping our audience make the most of our projects.
Please help us get ready so that our newbies will have an easier time learning the ropes of our beautiful projects.