We've put together RC1 for 1.22.0. Please test the tarball and report any bugs you find on Bugzilla: http://bugzilla.wikimedia.org/
Here are a list of changes made since the last RC. (Links for download follow this list.)
https://gerrit.wikimedia.org/r/#/c/94393/ Correct tooltip of "Next n results" on query special pages. -- Alexandre Emsenhuber
https://gerrit.wikimedia.org/r/#/c/94364/ Fix call to function applyPatch in MysqlUpdater -- umherirrender
https://gerrit.wikimedia.org/r/#/c/93120/ Make it possible to install extensions using Composer -- jeroendedauw
https://gerrit.wikimedia.org/r/#/c/92489/ FormatJson: Remove whitespace from empty arrays and objects -- Kevin Israel
https://gerrit.wikimedia.org/r/#/c/93704/ MWException: Cleanup exception message output -- Brad Jorsch
https://gerrit.wikimedia.org/r/#/c/93703/ redact exception traces and abstract getTrace -- Antoine Musso
https://gerrit.wikimedia.org/r/#/c/92545/ UploadStash::removeFileNoAuth shouldn't need auth -- Brad Jorsch
https://gerrit.wikimedia.org/r/#/c/94119/ MySQL method to find out view + fix fatal in tests -- AlephNull
https://gerrit.wikimedia.org/r/#/c/94261/ wikibits: Add some missing deprecation messages -- Bartosz Dziewoński
https://gerrit.wikimedia.org/r/#/c/94256/ Migrate usage of wikibits in legacy protect.js and upload.js -- Timo Tijhof
https://gerrit.wikimedia.org/r/#/c/93702/ exception: Use MWExceptionHandler::logException in more places -- Timo Tijhof
https://gerrit.wikimedia.org/r/#/c/93701/ Distinguish redactions from the string "REDACTED" in formatRedactedTrace -- Brad Jorsch
https://gerrit.wikimedia.org/r/#/c/93987/ Change mode of non-executable files back to 0644 -- Alexandre Emsenhuber
https://gerrit.wikimedia.org/r/#/c/93971/ Mark Math-specific functions in core as deprecated -- Moritz Schubotz
https://gerrit.wikimedia.org/r/#/c/93412/ Vector: Set media screen on styles.less -- jrobson
https://gerrit.wikimedia.org/r/#/c/92990/ SkinTemplate: Move debug HTML above bottomscripts -- Bartosz Dziewoński
https://gerrit.wikimedia.org/r/#/c/92979/ mediawiki.inspect#dumpTable: fix broken FF workaround -- Ori Livneh
https://gerrit.wikimedia.org/r/#/c/92788/ Wrap up remaining legacy javascript (IEFixes, wikibits) -- Timo Tijhof
https://gerrit.wikimedia.org/r/#/c/92774/ vector: Restore gray search input placeholder -- Bartosz Dziewoński
https://gerrit.wikimedia.org/r/#/c/92770/ Vector: Remove media=screen from skins.vector.beta module -- Timo Tijhof
https://gerrit.wikimedia.org/r/#/c/92557/ Backport information boxes' styles from vforms to shared CSS -- MatmaRex
Full release notes: https://git.wikimedia.org/blob/mediawiki%2Fcore.git/1.22.0rc1/RELEASE-NOTES-... https://www.mediawiki.org/wiki/Release_notes/1.22
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