Mentors using the Growth Mentor dashboard will now see newcomers assigned to them who have made at least one edit, up to 200 edits. Previously, all newcomers assigned to the mentor were visible on the dashboard, even ones without any edit or ones who made hundred of edits. Mentors can still change these values using the filters on their dashboard. Also, the last choice of filters will now be saved.
The user group oversight was renamed suppress. This is for technical reasons. You may need to update any local references to the old name, e.g. gadgets, links to Special:Listusers, or uses of NUMBERINGROUP.
The recent change to the HTML of tracking changes pages caused some problems for screenreaders. This is being fixed.
Changes later this week
The new version of MediaWiki will be on test wikis and MediaWiki.org from 1 March. It will be on non-Wikipedia wikis and some Wikipedias from 2 March. It will be on all wikis from 3 March (calendar).
Working with templates will become easier. Several improvements are planned for March 9 on most wikis and on March 16 on English Wikipedia. The improvements include: Bracket matching, syntax highlighting colors, finding and inserting templates, and related visual editor features.
If you are a template developer or an interface administrator, and you are intentionally overriding or using the default CSS styles of user feedback boxes (the classes: successbox, messagebox, errorbox, warningbox), please note that these classes and associated CSS will soon be removed from MediaWiki core. This is to prevent problems when the same class-names are also used on a wiki. Please let us know by commenting at phab:T300314 if you think you might be affected.