On 8 September 2015 at 20:50, Sam Smith <samsmith@wikimedia.org> wrote:

The patch that introduced the bug was merged on Tuesday, 25th August, which, I think, means that it'd have been deployed on Thursday, 3rd September – that's a long weekend's worth of data that we won't see again.

The deployment schedule is not quite that simple. If you open the 'Included in' section of the breaking commit, you can see it was included in wmf/1.26wmf21. According to https://www.mediawiki.org/wiki/MediaWiki_1.26/Roadmap that was deployed to mediawiki.org, zero.wikimedia.org and some test wikis on the 1st, most wikis on the 2nd, and then only Wikipedias on the 3rd.