According to the Version lifecycle[1], MediaWiki 1.22 is slated for release on November 30th, at the very latest.
In that vein, we've come up with a timeline for the release[2]. If we use this timeline and shoot for the latest date, we'll need to start the release process no later than October 19th. Please look over the timeline and the "TBD" section and provide feedback.
Of course, if you see gaps or things that you can help clarify, please feel free to mention them on the talk page.
Thanks,
Mark.
[1] https://www.mediawiki.org/wiki/Version_lifecycle [2] https://www.mediawiki.org/wiki/Project:Release_management/Release_timeline