creation of passwordless "system" users for logged actions.
* $wgMaxSquidPurgeTitles was removed.
* $wgAjaxWatch was removed. This is now enabled by default.
-* (T27397) WebP is enabled by default as an uploadable filetype
+* $wgUseInstantCommons now hotlinks Commons images by default instead of
+ downloading originals and thumbnailing them locally. This allows wikis to save
+ on CPU and bandwidth while reducing time to first byte for pages, even without
+ a thumbnail handler. See $wgForeignFileRepos documentation for tweaks.
+* (T27397) WebP is enabled by default as an uploadable filetype.
+* (T48998) $wgArticlePath must now be either a full url, or start with a "/".
+* $wgRateLimitLog was removed; use $wgDebugLogGroups['ratelimit'] instead.
+* Deprecated API formats dbg, txt, and yaml have been removed.
+* CLDRPluralRule* classes have been replaced with wikimedia/cldr-plural-rule-parser.
+* Removed $wgProfilePerHost, $wgUDPProfilerHost, $wgUDPProfilerPort,
+ $wgUDPProfilerFormatString, $wgStatsMethod, $wgAggregateStatsID, $wgStatsFormatString,
+ and $wgProfileCallTree (deprecated since 1.20).
=== New features in 1.27 ===
* $wgDataCenterId and $wgDataCenterRoles where added, which will serve as
* Extensions can now return detailed error information via the API when
preventing user actions using 'getUserPermissionsErrors' and similar hooks
by using ApiMessage instances instead of strings for the $result value.
-
-==== External libraries ====
+* $wgAPIMaxLagThreshold was added to limit bot changes when databases lag
+ becomes too high.
+* Skins and extensions can now use FlexBox mixins (.flex-display(@display: flex)
+ and .flex(@grow: 1, @shrink: 1, @width: auto, @order: 1)) in Less to create
+ cross-browser-compatible FlexBox rules. Users will still need to add fallback
+ float rules or the like for compatibility with IE9- separately.
+* Added MWTimestamp::getTimezoneString() which returns the localized timezone
+ string, if available. To localize this string, see the comments of
+ $wgLocaltimezone in includes/DefaultSettings.php.
+* Added CentralIdLookup, a service that allows extensions needing a concept of
+ "central" users to get that without having to know about specific central
+ authentication extensions.
+* $wgMaxUserDBWriteDuration added to limit huge user-generated transactions.
+ Regular web request transactions that takes longer than this are aborted.
+
+=== External library changes in 1.27 ===
+==== Upgraded external libraries ====
+* Updated oojs/oojs-ui from v0.12.12 to v0.13.3.
+* Updated composer/semver from v1.0.0 to v1.2.0.
+* Update liuggio/statsd-php-client to 1.0.18.
+
+==== New external libraries ====
+* Added wikimedia/base-convert v1.0.1.
+* Added wikimedia/cldr-plural-rule-parser v1.0.0.
+* Added wikimedia/relpath v1.0.3.
+* Added wikimedia/running-stat v1.1.0.
+
+==== Removed and replaced external libraries ====
=== Bug fixes in 1.27 ===
+* Special:Upload will now display correct maximum allowed file size when running
+ under HHVM (T116347).
=== Action API changes in 1.27 ===
* Added list=allrevisions.
"was-deleted" warning.
* Added difftotextpst to query=revisions which preforms a pre-save transform on
the text before diffing it.
+* Deprecated formats dbg, txt, and yaml have been removed.
+* (T47988) The protect log event details now use new-style formatting.
=== Action API internal changes in 1.27 ===
* ApiQueryORM removed.
+* The following classes have been removed:
+** ApiFormatDbg
+** ApiFormatTxt
+** ApiFormatYaml
+* ApiQueryBase::getDirectionDescription is now marked as deprecated. It should
+ have been so marked since 1.25 when ApiBase::getParamDescription was
+ deprecated, but was overlooked at the time.
=== Languages updated in 1.27 ===
MediaWiki supports over 350 languages. Many localisations are updated
regularly. Below only new and removed languages are listed, as well as
-changes to languages because of Bugzilla reports.
+changes to languages because of Phabricator reports.
* (T113688) Change default numerals from Gurmukhi to Arabic for Punjabi locale.
* LinkCache::getGoodLinks and LinkCache::getBadLinks were removed (deprecated in 1.26).
* WikiPage::doQuickEdit() was removed (deprecated since 1.21).
* Removed SiteObject and SiteArray classes (deprecated in 1.21).
+* MessageBlobStore::getInstance() was removed (deprecated since 1.25).
+* (T84937) Free external links ("autolinked" urls) will now be terminated
+ by and HTML entity encodings of  , <, and >.
+* (T36948) The default file revert message's timestamp is now in $wgLocaltimezone,
+ instead of UTC.
+* The default name of the 'suppress' group page has been changed from
+ 'Project:Oversight' to 'Project:Suppress'.
+* DatabaseBase::resultObject() is now protected (use outside Database classes
+ not necessary since 1.11).
+* Calling ResourceLoaderFileModule::readStyleFiles() without a
+ ResourceLoaderContext instance is deprecated.
+* ResourceLoader::getLessCompiler() now takes an optional parameter of
+ additional LESS variables to set for the compiler.
+* wfBaseConvert() marked as deprecated, use Wikimedia\base_convert() directly instead.
+* Obsolete maintenance scripts clearCacheStats.php and showCacheStats.php
+ were removed. The underlying data is sent to StatsD (see $wgStatsdServer).
== Compatibility ==