This is a notice that on Tuesday, Jan 28th between 21:00-22:00 UTC (1-2pm
PST) Wikimedia Foundation will release critical security updates for
current and supported branches of the MediaWiki software and extensions.
Downloads and patches will be available at that time, with the git
repositories updated soon after. The vulnerable feature is not enabled in
MediaWiki by default, however many sites will want to upgrade as soon as
the patch is available.