User blog comment:Kirkburn/Technical Update: April 13, 2015/@comment-1341868-20150428005919/@comment-452-20150428011812

The update should occur within 12 to 18 hours from now. :)

Edit: it updated 8 hours from when I originally posted this, so apparently updates are happening earlier these days, possibly having something to do with the schedule change. (But it may not update on all wikis at once.)