MediaWiki 1.19/Post-deploy retrospective

We deployed MediaWiki 1.19 in February 2012. In the interests of doing better next time, please help us brainstorm what went right and what we need to look at. RobLa will then summarize that discussion.

Note: this is specifically about the MediaWiki 1.19 deployment, rather than the 1.19.0 release.

There are two sections: "What went well?" and "What do we need to look at?" For now, limit input to small (<140 character) bullet items. If you want to elaborate or respond, please take it to the Talk page.

What went well?

 * Pre-deploy testing of Commons gadgets on http://labs.wikimedia.beta.wmflabs.org/
 * Gross errors detected quickly, rollbacks were effective and fast.
 * Most of the big bugs got shaken out prior to the *.wikipedia.org deployment
 * Detailed communication plan, well in advance
 * No deathmarches. A couple of the windows went over their time, but they weren't huge marathons.
 * Most schema changes were done well in advance

What do we need to look at?

 * Swift?
 * We misread the severity of broken thumb reports
 * Release notes were unorganized, hard to interpret, possibly inaccurate
 * Editors asked more than once "What has changed" and it was hard to give an answer. MediaWiki 1.18 did this much better.
 * Should we have a watchlist notice on top wikis?
 * Lots of Javascript breakage that we might have been able to test sooner
 * Need to test language variants prior to deployment
 * Need to make sure we're not scheduling right on top of key personnel vacation (1.19: Asher)
 * Possible to do schema changes even earlier or independent of deploy cycle?