The Video2commons tool has been updated. This fixed several bugs related to YouTube uploads.
The Especial:Preferências page has been redesigned on mobile web. The new design makes it easier to browse the different categories and settings at low screen widths. You can also now access the page via a link in the Settings menu in the mobile web sidebar.
Changes later this week
The new version of MediaWiki will be on test wikis and MediaWiki.org from 2 May. It will be on non-Wikipedia wikis and some Wikipedias from 3 May. It will be on all wikis from 4 May (calendar).