MediaWiki 1.20/wmf2

Deployment of MediaWiki 1.20wmf2 to Wikimedia sites
The latest version (labeled "1.20wmf2") of MediaWiki, the software that powers Wikipedia and its sister sites, is currently being deployed to all Wikimedia sites in stages.

We started on April 30th and will continue until May 9th (see the roadmap).

We will continue to deploy the latest software every two weeks. This is intended to minimize disruption and possible issues, and make it easier to identify the cause of problems, since the possibly problematic code will be much more recent.

What's new
This is a very small set of changes, compared to the previous deployments, as this represents only the development activity between April 10 and April 30:
 * Core features
 * Adds high definition (HD) CSS for the Vector skin
 * Add missing uploads link to deleted contributions.
 * Edit notices can now be translated.
 * Core bugfixes
 * : allow moving files with rows with bad oi_archive_name values.
 * Fix group addition/removal messages on Special:Listgrouprights
 * BiDi: Embed links for parent pages according to content language by adding dirmarks.
 * &lt;title&gt; empty on Sanskrit Wikipedia
 * Fix pre-upload preview on IE 10 for Special:Upload
 * new optional 'link' parameter to &lt;gallery&gt;
 * - when guessVariant is true, -{}- is not parsed but it is sometimes needed
 * list=allusers throws exceptions with invalid names
 * Remove 10000x10000 pixel option in preferences
 * fix the navigation with 'dir'
 * Add a word-separator between help-messages in HTMLForm
 * Space in $separatorTransformTable should be non-breaking in Portuguese, Esperanto and Udmurt.
 * Extensions
 * AbuseFilter
 * Diffs on some /details views are stretched horizontally.
 * AntiSpoof
 * - Fixed a character equivalence issue (equivset: 3A5 Υ =&gt; 59 Y)
 * CentralAuth
 * Remove yaseo references
 * CentralNotice
 * Adding documentation and class visibility to class.
 * CheckUser
 * ARIN WHOIS link rot fixed.
 * FlaggedRevs
 * [FlaggedRevs] Section anchor link encoding fixes for.
 * LiquidThreads
 * - Fix for problem with API prop=info with invalid titles
 * Math
 * Update math parser test cases for new rendering defaults
 * MoodBar
 * Several RTL fixes (including and )
 * Narayam
 * Do not check the string length of regular expression.
 * Fixing the rule for ~ in Tamil transliteration
 * Improvements for Punjabi transliteration.
 * Move te transliteration out of beta status
 * ProofreadPage
 * The scan does not appear on Opera.
 * Add 'onlysection' parameter to &lt;pages/&gt;.
 * &lt;pagelist/&gt; should show localized page numbers
 * Anonymous users cannot change page status
 * Position of quality buttons should not change
 * &lt;pages&gt; transclusions allow for infinite loop
 * Fix fromsection and tosection system in the "pages" tag.
 * Add 'onlysection' parameter to &lt;pages/&gt;.
 * Fix an exception thrown when viewing the page.
 * SyntaxHighlight_GeSHi
 * Fix display problems by using CSS classes .mw-code and .mw-code-inline
 * Translate
 * Better comparing of fuzzy translations
 * Disabled page translation links on mobile site until Translate supports mobile:)
 * Special:ManageMessageGroups performance improvements
 * UploadWizard
 * Weird behavior when clicking on the name or the thumbnail of the file
 * Fix pre-upload preview on IE 10 for Special:UploadWizard
 * Experimental opt-in mode for UploadWizard's chunked uploads feature
 * Fix display order of uploaded files.
 * Large Thumbnail Preview popup has scrollbar
 * show error if selected file is too large
 * Support chunked uploads in IE 10
 * WebFonts
 * Add supports for fonts with style variants
 * WikiEditor
 * Adding Tamil numerals special character insertion toolbar.
 * Fixes issue where old toolbar was killed, even when the new toolbar was incompatible
 * Adding pretty quotation marks for Hebrew.
 * Moved character 25cc (dotted circle) before the diacritic.
 * RTL fix for special characters insertion links.
 * Updating the Gujarati character insertion toolbar.
 * modified as per
 * WikiLove
 * better SVG icon
 * Developer features and fixes:
 * Update jQuery UI to 1.8.19
 * Many FileBackend and FileRepo changes to improve Swift usage
 * Minor improvements to memcache client (BagOStuff)
 * Fixed incorrect hash mismatch errors in the DiffHistoryBlob
 * Added GitViewers hook for extensions using external git repositories to have a web-based repository viewer linked to from Special:Version.
 * Add warning and tracking category for preprocessor errors
 * Removed deprecated $wgFilterCallback and the 'filtered' API error.
 * Parser should use mUrlProtocol instead of wfUrlProtocols
 * Remove deprecated $wgFilterCallback. The 'filtered' API error was also removed, along with EditPage::AS_FILTERING.
 * More refactoring to use context objects instead of globals
 * Refactoring previewnote.
 * Removed unnecessary width:auto on header elements
 * Disable CSS concatenation, breaks @import
 * Add section with entry point URLs to Special:Version
 * Fix magic $ aliasing in ResourceLoader
 * New DBDataObject ORM implementation
 * New CacheHelper: facilitate caching handling on a page
 * New Language::formatDuration method
 * Deprecate WebRequest::escapeAppendQuery
 * Make API action=tokens extendable
 * Add function OutputPage::getHeadLinksArray
 * - Adding TranslationNotifications
 * fix min and max parameters in list=allcategories
 * Corrected capitalization in the file and class names of API modules
 * Hash comparison should always be strict.
 * support for in jqueryMsg
 * Add a word-separator between help-messages in HTMLForm
 * Pre-register default-loaded RL modules in the client-side

Developers have also improved the software "under the hood" in many ways. A more detailed list of changes can be found in the draft release notes.

If you encounter issues
If, despite our efforts, you encounter issues due to the upgrade; we'll try and fix them as soon as we can. Please report issues [//bugzilla.wikimedia.org/enter_bug.cgi?product=MediaWiki&version=1.20-git in our bug tracker], which is where we look for reports of problems. And the faster you tell us about problems, the faster we can address them.