RELEASE-NOTES-1.27

   1 == MediaWiki 1.27 ==
   2
   3 THIS IS NOT A RELEASE YET
   4
   5 MediaWiki 1.27 is an alpha-quality branch and is not recommended for use in
   6 production.
   7
   8 === PHP version requirement ===
   9 As of 1.27, MediaWiki now requires PHP 5.5.9 or higher. This corresponds with
  10 HHVM 3.1. Additionally, the following PHP extensions are required:
  11 * ctype
  12 * iconv
  13 * json
  14 * mbstring
  15 * xml
  16
  17 === Configuration changes in 1.27 ===
  18 * $wgAllowMicrodataAttributes and $wgAllowRdfaAttributes were removed,
  19   now always enabled. If you use RDFa on your wiki, you now have to explicitly
  20   set $wgHtml5Version to 'HTML+RDFa 1.0' or 'XHTML+RDFa 1.0'.
  21 * $wgUseLinkNamespaceDBFields was removed.
  22 * Deprecated $wgResourceLoaderMinifierStatementsOnOwnLine and
  23   $wgResourceLoaderMinifierMaxLineLength, because there was little value in
  24   making the behavior configurable. The default values (`false` for the former,
  25   1000 for the latter) are now hard-coded.
  26 * $wgDebugDumpSqlLength was removed (deprecated in 1.24).
  27 * $wgDebugDBTransactions was removed (deprecated in 1.20).
  28 * $wgUseXVO has been removed, as it provides functionality only used by
  29   custom Wikimedia patches against Squid 2.x that probably noone uses in
  30   production anymore. There is now $wgUseKeyHeader that provides similar
  31   functionality but instead of the MediaWiki-specific X-Vary-Options header,
  32   uses the draft Key header standard.
  33 * $wgScriptExtension (and support for '.php5' entry points) was removed. See the
  34   deprecation notice in the release notes for version 1.25 for advice on how to
  35   preserve support for '.php5' entry points via URL rewriting.
  36 * Password handling via the User object has been deprecated and partially
  37   removed, pending the future introduction of AuthManager. In particular:
  38 ** expirePassword(), getPasswordExpireDate(), resetPasswordExpiration(), and
  39    getPasswordExpired() have been removed. They were unused outside of core.
  40 ** The mPassword, mNewpassword, mNewpassTime, and mPasswordExpires fields are
  41    now private and will be removed in the future.
  42 ** The getPassword() and getTemporaryPassword() methods now throw
  43    BadMethodCallException and will be removed in the future.
  44 ** The ability to pass 'password' and 'newpassword' to createNew() has been
  45    removed. The only users of it seem to have been using it to set invalid
  46    passwords, and so shouldn't be greatly affected.
  47 ** setPassword(), setInternalPassword(), and setNewpassword() have been
  48    deprecated, pending the introduction of AuthManager.
  49 ** User::randomPassword() is deprecated in favor of a new method
  50    PasswordFactory::generateRandomPasswordString()
  51 ** User::getPasswordFactory() is deprecated, callers should just create a
  52    PasswordFactory themselves.
  53 ** A new constructor, User::newSystemUser(), has been added to simplify the
  54    creation of passwordless "system" users for logged actions.
  55 * $wgMaxSquidPurgeTitles was removed.
  56 * $wgAjaxWatch was removed. This is now enabled by default.
  57 * $wgUseInstantCommons now hotlinks Commons images by default instead of
  58   downloading originals and thumbnailing them locally. This allows wikis to save
  59   on CPU and bandwidth while reducing time to first byte for pages, even without
  60   a thumbnail handler. See $wgForeignFileRepos documentation for tweaks.
  61 * (T27397) WebP is enabled by default as an uploadable filetype.
  62 * (T48998) $wgArticlePath must now be either a full url, or start with a "/".
  63 * $wgRateLimitLog was removed; use $wgDebugLogGroups['ratelimit'] instead.
  64 * Deprecated API formats dbg, txt, and yaml have been removed.
  65 * CLDRPluralRule* classes have been replaced with
  66   wikimedia/cldr-plural-rule-parser.
  67 * Removed $wgProfilePerHost, $wgUDPProfilerHost, $wgUDPProfilerPort,
  68   $wgUDPProfilerFormatString, $wgStatsMethod, $wgAggregateStatsID,
  69   $wgStatsFormatString, and $wgProfileCallTree (deprecated since 1.20).
  70 * For proper operation of LocalIdLookup with shared user tables, ensure that
  71   $wgSharedDB and $wgSharedTables are properly set even on the "central" wiki
  72   that all others are sharing from and that $wgLocalDatabases is set to the
  73   full list of sharing wikis on all those wikis.
  74 * Massive overhaul to session handling:
  75 ** $wgSessionsInObjectCache is no longer supported and must be true, due to
  76    MediaWiki\Session\SessionManager. $wgSessionHandler is similarly no longer
  77    used.
  78 ** ObjectCacheSessionHandler is removed, replaced with
  79    MediaWiki\Session\PhpSessionHandler.
  80 ** PHP session handling in general ($_SESSION, session_id(), and so on) is
  81    deprecated. Use MediaWiki\Session\SessionManager instead. A new config
  82    variable, $wgPHPSessionHandling, is available to cause use of $_SESSION to
  83    issue a deprecation warning or to cause most PHP session handling to throw
  84    exceptions.
  85 ** Deprecated UserSetCookies hook. Session-handling extensions should generally
  86    be creating a custom subclass of CookieSessionProvider. Other extensions
  87    messing with cookies can no longer count on user data being saved in cookies
  88    versus other methods.
  89 ** Deprecated UserLoadFromSession hook, extensions should create a
  90    MediaWiki\Session\SessionProvider.
  91 ** The User cannot be loaded from session until after Setup.php completes.
  92    Attempts to do so will be ignored and the User will remain unloaded.
  93 ** CSRF tokens may be fetched from the MediaWiki\Session\Session, which uses
  94    the MediaWiki\Session\Token class.
  95 * MediaWiki will now auto-create users as necessary, removing the need for
  96   extensions to do so. An 'autocreateaccount' right is added to allow
  97   auto-creation when 'createaccount' is not granted to all users.
  98 * Deprecated AuthPluginAutoCreate hook in favor of LocalUserCreated.
  99 * Most cookie-handling methods in User are deprecated.
 100 * $wgAllowAsyncCopyUploads and $CopyUploadAsyncTimeout were removed. This was an
 101   experimental feature that has never worked.
 102 * Login and createaccount tokens now vary by timestamp.
 103 * LoginForm::getLoginToken() and LoginForm::getCreateaccountToken()
 104   return a MediaWiki\Session\Token, and tokens must be checked using that
 105   class's methods.
 106 * $wgEnotifUseJobQ was removed and the job queue is always used.
 107 * The functionality of the ApiSandbox extension has been merged into core. The
 108   extension should no longer be used.
 109 * $wgPreloadJavaScriptMwUtil was removed (deprecated in 1.26).
 110   Extensions, skins, gadgets and scripts that use the mediawiki.util module must
 111   express a dependency on it.
 112 * $wgIncludeLegacyJavaScript, deprecated in MediaWiki 1.26, now defaults false.
 113   Extensions, skins, gadgets and scripts that need the mediawiki.legacy.wikibits
 114   module should express a dependency on it.
 115 * Removed configuration option $wgCopyrightIcon (deprecated since 1.18). Use
 116   $wgFooterIcons['copyright']['copyright'] instead.
 117
 118 === New features in 1.27 ===
 119 * $wgDataCenterUpdateStickTTL was also added. This decides how long a user
 120   sticks to the primary DC (via cookies) after they make changes to the site.
 121 * Added a new hook, 'UserMailerTransformContent', to transform the contents
 122   of an email. This is similar to the EmailUser hook but applies to all mail
 123   sent via UserMailer.
 124 * Added a new hook, 'UserMailerTransformMessage', to transform the contents
 125   of an emai after MIME encoding.
 126 * Added a new hook, 'UserMailerSplitTo', to control which users have to be
 127   emailed separately (ie. there is a single address in the To: field) so
 128   user-specific changes to the email can be applied safely.
 129 * $wgCdnMaxageLagged was added, which limits the CDN cache TTL
 130   when any load balancer uses a DB that is lagged beyond the 'max lag'
 131   setting in the relevant section of $wgLBFactoryConf.
 132 * User::newSystemUser() may be used to simplify the creation of passwordless
 133   "system" users for logged actions from scripts and extensions.
 134 * Extensions can now return detailed error information via the API when
 135   preventing user actions using 'getUserPermissionsErrors' and similar hooks
 136   by using ApiMessage instances instead of strings for the $result value.
 137 * $wgAPIMaxLagThreshold was added to limit bot changes when databases lag
 138   becomes too high.
 139 * Skins and extensions can now use FlexBox mixins (.flex-display(@display: flex)
 140   and .flex(@grow: 1, @shrink: 1, @width: auto, @order: 1)) in Less to create
 141   cross-browser-compatible FlexBox rules. Users will still need to add fallback
 142   float rules or the like for compatibility with IE9- separately.
 143 * Added MWTimestamp::getTimezoneString() which returns the localized timezone
 144   string, if available. To localize this string, see the comments of
 145   $wgLocaltimezone in includes/DefaultSettings.php.
 146 * Added CentralIdLookup, a service that allows extensions needing a concept of
 147   "central" users to get that without having to know about specific central
 148   authentication extensions.
 149 * $wgMaxUserDBWriteDuration added to limit huge user-generated transactions.
 150   Regular web request transactions that takes longer than this are aborted.
 151 * Added a new hook, 'TitleMoveCompleting', which runs before a page move is
 152   committed.
 153 * $wgCdnReboundPurgeDelay was added to provide secondary delayed purges of URLs
 154   from CDN to mitigate DB replication lag and WAN cache purge lag.
 155 * (T49162) Installer will default to setting CACHE_ACCEL as the main cache type
 156   if it is available.
 157 * It is now possible to patrol file uploads (both for new files and new versions
 158   of existing files). Special:NewFiles has gained an option to filter by patrol
 159   status. This functionality can be disabled using $wgUseFilePatrol.
 160 * MediaWiki\Session infrastructure allows for easier use of session mechanisms
 161   other than the usual cookies.
 162 ** SessionMetadata and SessionCheckInfo hooks allow for setting and checking
 163    custom session metadata.
 164 * Added MWGrants and associated configuration settings $wgGrantPermissions and
 165   $wgGrantPermissionGroups to hold configuration for authentication features
 166   such as OAuth that want to allow restricting the user rights a user may make
 167   use of.
 168 ** If you're already using the OAuth extension, these new variables are
 169    identical to (and will replace) $wgMWOAuthGrantPermissions and
 170    $wgMWOAuthGrantPermissionGroups.
 171 * Added MWRestrictions as a class to check restrictions on a WebRequest, e.g.
 172   to assert that the request comes from a particular IP range.
 173 * Added bot passwords, a rights-restricted login mechanism for API-using bots.
 174 * Whitelisted the following HTML attributes for all elements in wikitext:
 175   aria-describedby, aria-flowto, aria-label, aria-labelledby, aria-owns.
 176 * Removed "presentation" restriction on the HTML role attribute in wikitext.
 177   All values are now allowed for the role attribute.
 178 * $wgContentHandlers now also supports callbacks to create an instance of the
 179   appropriate ContentHandler subclass.
 180 * Added $wgAuthenticationTokenVersion, which if non-null prevents the
 181   user_token database field from being exposed in cookies. Setting this would
 182   be a good idea, but will log out all current sessions.
 183 * $wgEventRelayerConfig was added, for managing PubSub event relay configuration,
 184   specifically for reliable CDN url purges.
 185 * Requests have unique IDs, equal to the UNIQUE_ID environment variable (when
 186   MediaWiki is behind Apache+mod_unique_id or something similar) or a randomly-
 187   generated 24-character string. This request ID is used to annotate log records
 188   and error messages. It is available client-side via mw.config.get( 'wgRequestId' ).
 189   The request ID supplants exception IDs. Accordingly, MWExceptionHandler::getLogId()
 190   is deprecated.
 191
 192 === External library changes in 1.27 ===
 193
 194 ==== Upgraded external libraries ====
 195 * Updated oojs/oojs-ui from v0.12.12 to v0.13.3.
 196 * Updated composer/semver from v1.0.0 to v1.2.0.
 197 * Updated liuggio/statsd-php-client to 1.0.18.
 198 * Updated QUnit from v1.18.0 to v1.22.0.
 199
 200 ==== New external libraries ====
 201 * Added wikimedia/base-convert v1.0.1.
 202 * Added wikimedia/cldr-plural-rule-parser v1.0.0.
 203 * Added wikimedia/relpath v1.0.3.
 204 * Added wikimedia/running-stat v1.1.0.
 205 * Added wikimedia/php-session-serializer v1.0.3.
 206
 207 ==== Removed and replaced external libraries ====
 208
 209 === Bug fixes in 1.27 ===
 210 * Special:Upload will now display correct maximum allowed file size when running
 211   under HHVM (T116347).
 212
 213 === Action API changes in 1.27 ===
 214 * Added list=allrevisions.
 215 * generator=recentchanges now has the option to generate revids.
 216 * ApiPageSet::setRedirectMergePolicy() was added. This allows generator
 217   modules to define how generator data for a redirect source gets merged
 218   into the redirect destination.
 219 * prop=imageinfo&iiprop=uploadwarning will no longer include the possibility of
 220   "was-deleted" warning.
 221 * Added difftotextpst to query=revisions which preforms a pre-save transform on
 222   the text before diffing it.
 223 * Deprecated formats dbg, txt, and yaml have been removed.
 224 * (T47988) The protect log event details now use new-style formatting.
 225 * The following response properties from action=login are deprecated, and may
 226   be removed in the future: lgtoken, cookieprefix, sessionid. Clients should
 227   handle cookies to properly manage session state.
 228 * action=login transparently allows login using bot passwords. Clients should
 229   merely need to change the username and password used after setting up a bot
 230   password.
 231 * action=upload no longer understands statuskey, asyncdownload or leavemessage.
 232
 233 === Action API internal changes in 1.27 ===
 234 * ApiQueryORM removed.
 235 * The following classes have been removed:
 236 ** ApiFormatDbg
 237 ** ApiFormatTxt
 238 ** ApiFormatYaml
 239 * ApiBase::addTokenProperties() was removed (deprecated since 1.24).
 240 * ApiBase::getFinalPossibleErrors() was removed (deprecated since 1.24).
 241 * ApiBase::getFinalResultProperties() was removed (deprecated since 1.24).
 242 * ApiBase::getRequireAtLeastOneParameterErrorMessages() was removed (deprecated since 1.24).
 243 * ApiBase::getPossibleErrors() was removed (deprecated since 1.24).
 244 * ApiBase::getRequireMaxOneParameterErrorMessages() was removed (deprecated since 1.24).
 245 * ApiBase::getRequireOnlyOneParameterErrorMessages() was removed (deprecated since 1.24).
 246 * ApiBase::getResultProperties() was removed (deprecated since 1.24).
 247 * ApiBase::getTitleOrPageIdErrorMessage() was removed (deprecated since 1.24).
 248 * ApiBase::parseErrors() was removed (deprecated since 1.24).
 249 * ApiQueryBase::titleToKey(), ApiQueryBase::keyToTitle() and
 250   ApiQueryBase::keyPartToTitle() all removed (deprecated since 1.24).
 251 * ApiQueryBase::checkRowCount() was removed (deprecated since 1.24).
 252 * ApiQueryBase::getDirectionDescription() was removed (deprecated since 1.25).
 253 * ApiQuery::getGenerators() was removed (deprecated since 1.21).
 254 * ApiQuery::getModules() was removed (deprecated since 1.21).
 255 * ApiQuery::getModuleType() was removed (deprecated since 1.21).
 256 * ApiQuery::setGeneratorContinue() was removed (deprecated since 1.24).
 257 * ApiMain::getModules() was removed (deprecated since 1.21).
 258 * ApiBase::getVersion() was removed (deprecated since 1.21).
 259 * ApiMain::getShowVersions() was removed (deprecated in 1.21).
 260 * ApiMain::addModule() was removed (deprecated in 1.21).
 261 * ApiMain::addFormat() was removed (deprecated in 1.21).
 262 * ApiMain::getFormats() was removed (deprecated in 1.21).
 263 * ApiPageSet::finishPageSetGeneration() was removed (deprecated in 1.21).
 264
 265 === Languages updated in 1.27 ===
 266
 267 MediaWiki supports over 350 languages. Many localisations are updated
 268 regularly. Below only new and removed languages are listed, as well as
 269 changes to languages because of Phabricator reports.
 270
 271 * (T113688) Change default numerals from Gurmukhi to Arabic for Punjabi locale.
 272 * (T116020) Aliases of magic words in MessagesXx.php are sorted by usage.
 273
 274 === Other changes in 1.27 ===
 275 * Added dependency injection (DI) infrastructure, see docs/injection.txt for details.
 276   It is planned to incrementally move MediaWiki code towards using DI, using the
 277   service locator (SL) pattern as a stepping stone.
 278 * ProfilerOutputUdp was removed. Note that there is a ProfilerOutputStats class.
 279 * WikiPage::doDeleteArticleReal() and WikiPage::doDeleteArticle() now
 280   ignore the 2nd and 3rd arguments (formerly $id and $commit).
 281 * Removed "loaderScripts" option from ResourceLoaderFileModule class.
 282 * Removed ORM-like wrapper added in 1.20.
 283 * LinkCache::getGoodLinks and LinkCache::getBadLinks were removed
 284   (deprecated in 1.26).
 285 * WikiPage::doQuickEdit() was removed (deprecated since 1.21).
 286 * Removed SiteObject and SiteArray classes (deprecated in 1.21).
 287 * MessageBlobStore::getInstance() was removed (deprecated since 1.25).
 288 * (T84937) Free external links ("autolinked" urls) will now be terminated
 289   by &nbsp; and HTML entity encodings of &nbsp, <, and >.
 290 * (T36948) The default file revert message's timestamp is now in
 291   $wgLocaltimezone, instead of UTC.
 292 * The default name of the 'suppress' group page has been changed from
 293   'Project:Oversight' to 'Project:Suppress'.
 294 * DatabaseBase::resultObject() is now protected (use outside Database classes
 295   not necessary since 1.11).
 296 * Calling ResourceLoaderFileModule::readStyleFiles() without a
 297   ResourceLoaderContext instance is deprecated.
 298 * ResourceLoader::getLessCompiler() now takes an optional parameter of
 299   additional LESS variables to set for the compiler.
 300 * wfBaseConvert() marked as deprecated, use Wikimedia\base_convert() directly
 301   instead.
 302 * Obsolete maintenance scripts clearCacheStats.php and showCacheStats.php
 303   were removed. The underlying data is sent to StatsD (see $wgStatsdServer).
 304 * Removed msg_resource_links database table and associated code.
 305 * Removed msg_resource database table and associated code.
 306 * Skin::getNamespaceNotice() was removed.
 307 * wfIsConfiguredProxy() was removed (deprecated since 1.24).
 308 * wfDebugTimer() was removed (deprecated since 1.25).
 309 * wfIsTrustedProxy() was removed (deprecated since 1.24).
 310 * wfGetIP() was removed (deprecated since 1.19).
 311 * MWHookException was removed.
 312 * OutputPage::appendSubtitle() was removed (deprecated since 1.19).
 313 * OutputPage::loginToUse() was removed (deprecated since 1.19).
 314 * Article::loadContent() was removed (deprecated since 1.19).
 315 * User::editToken() was removed (deprecated since 1.19).
 316 * Removed --force-normal option of dumpBackup.php, as it no longer served
 317   any useful purpose since 1.22.
 318 * The functions processOption() and processArgs() on the BackupDumper and
 319   TextPassDumper classes have been removed.
 320 * The maintenance/backupTextPass.inc file was deleted. You should include
 321   maintenance/dumpTextPass.php instead.
 322 * WikiPage::getUsedTemplates() was removed (deprecated since 1.19).
 323 * wfEmptyMsg() was removed (deprecated since 1.18).
 324 * OutputPage::permissionRequired() was removed (deprecated since 1.18).
 325 * OutputPage::blockedPage() was removed (deprecated since 1.18).
 326 * User::getSkin() was removed (deprecated since 1.18).
 327 * OutputPage::includeJQuery() was removed (deprecated since 1.17).
 328 * WikiPage::updateRestrictions() was removed (deprecated since 1.19).
 329 * WikiPage::testPreSaveTransform() was removed (deprecated since 1.19).
 330 * LogPage::logName() was removed (deprecated since 1.19).
 331 * LogPage::logHeader() was removed (deprecated since 1.19).
 332 * wfCheckLimits() was removed (deprecated since 1.24).
 333 * Linker::makeKnownLinkObj() was removed (deprecated since 1.16).
 334 * Linker::makeLinkObj() was removed (deprecated since 1.16).
 335 * wfMsgForContentNoTrans() was removed (deprecated since 1.18).
 336 * ChangesList::usePatrol was removed (deprecated since 1.22).
 337 * wfMsgNoTrans() was removed (deprecated since 1.18).
 338 * Linker::makeImageLink2 was removed (deprecated since 1.20).
 339 * Title::userIsWatching() was removed (deprecated since 1.20).
 340 * Removed WaitForSlave maintenance script; use SELECT MASTER_POS_WAIT()
 341   database function directly instead.
 342 * wfMsg() was removed (deprecated since 1.18).
 343 * wfMsgForContent() was removed (deprecated since 1.18).
 344 * wfMsgReal() was removed (deprecated since 1.18).
 345 * wfMsgGetKey() was removed (deprecated since 1.18).
 346 * wfMsgHtml() was removed (deprecated since 1.18).
 347 * wfMsgWikiHtml() was removed (deprecated since 1.18).
 348 * wfMsgExt() was removed (deprecated since 1.18).
 349 * Language::armourMath() was removed (deprecated since 1.22).
 350 * LanguageConverter::armourMath() was removed (deprecated since 1.22).
 351 * FakeConverter::armourMath() was removed (deprecated since 1.22).
 352 * The unused jquery.validate ResourceLoader module was removed.
 353 * FileRepo::getRootUrl() was removed (deprecated since 1.20).
 354 * User::generateToken() was removed (deprecated since 1.20).
 355 * WikiPage::getRawText() was removed (deprecated since 1.21).
 356 * ParserOutput::hasCustomDataUpdates() was removed (deprecated since 1.25).
 357 * ParserOutput::addSecondaryDataUpdate() was removed (deprecated since 1.25).
 358 * ParserOutput::getSecondaryDataUpdates() was removed (deprecated since 1.25).
 359 * Gallery images with multiple caption pipes no longer concatenate them all
 360   together but instead pick the final one, similar to image syntax.
 361 * XML-like parser tags (such as <gallery>), when unclosed, will be left unparsed
 362   rather than consume everything until the end of the page.
 363 * New maintenance script resetUserEmail.php allows sysadmins to reset user emails in case
 364   a user forgot password/account was stolen.
 365 * wfCheckEntropy() was removed (deprecated in 1.27).
 366 * Browser support for Internet Explorer 8 lowered from Grade A to Grade C.
 367 * ContentHandler::supportsCategories method added. Default is true.
 368   CategoryMembershipChangeJob updates are skipped for content that
 369   does not support categories.
 370 * wikidiff difference engine is no longer supported, anyone still using it are encouraged
 371   to upgrade to wikidiff2 which is actively maintained and has better package availability.
 372 * Database logic was removed from WatchedItem and a WatchedItemStore was created:
 373 ** WatchedItem::IGNORE_USER_RIGHTS and WatchedItem::CHECK_USER_RIGHTS were deprecated.
 374    User::IGNORE_USER_RIGHTS and User::CHECK_USER_RIGHTS were introduced.
 375 ** WatchedItem::fromUserTitle was deprecated in favour of the constructor.
 376 ** WatchedItem::resetNotificationTimestamp was deprecated.
 377 ** WatchedItem::batchAddWatch was deprecated.
 378 ** WatchedItem::addWatch was deprecated.
 379 ** WatchedItem::removeWatch was deprecated.
 380 ** WatchedItem::isWatched was deprecated.
 381 ** WatchedItem::duplicateEntries was deprecated.
 382 ** EmailNotification::updateWatchlistTimestamp was deprecated.
 383 ** User::getWatchedItem was removed.
 384 * Unit tests don't work with external PHPUnit anymore, Composer is now the only supported
 385   way. Run `composer install` to install it and other dev dependencies to run unit tests.
 386 * wl_id field added to the watchlist table.
 387 * Revision::getRawText() was removed (deprecated since 1.21).
 388 * WikiPage::replaceSection() was removed (deprecated since 1.21).
 389 * Article::replaceSection() was removed (deprecated since 1.21).
 390 * Language::getLangObj() was removed (deprecated since 1.24).
 391 * Language::getLanguageName() was removed (deprecated since 1.20).
 392 * Language::getLanguageNames() was removed (deprecated since 1.20).
 393 * Language::getTranslatedLanguageNames() was removed (deprecated since 1.20).
 394 * Language::specialPage() was removed (deprecated since 1.24).
 395 * MediaWikiTestCase::assertException() was removed (deprecated since 1.22).
 396 * OutputPage::getHeadItems() was removed (deprecated since 1.24).
 397 * OutputPage::getScript() was removed (deprecated since 1.24).
 398 * OutputPage::out() was removed (deprecated since 1.22).
 399 * OutputPage::setAllowedModules() was removed (deprecated since 1.24).
 400 * UserrightsPage::makeGroupNameListForLog() was removed (deprecated since 1.21).
 401 * MediaWikiSite::newFromGlobalId() was removed (deprecated since 1.21).
 402 * Title::newFromRedirect() was removed (deprecated since 1.21).
 403 * Skin::commonPrintStylesheet() was removed (deprecated since 1.22).
 404 * Skin::getCommonStylePath() was removed (deprecated since 1.24).
 405 * Skin::newFromKey() was removed (deprecated since 1.24).
 406 * Skin::getUsableSkins() was removed (deprecated since 1.23).
 407 * LoadBalancer::pickRandom() was removed (deprecated in 1.21).
 408 * Article::getUndoText() and WikiPage::getUndoText were removed (deprecated since
 409   1.21).
 410 * DifferenceEngine::setText() was removed (deprecated in 1.21).
 411 * Title::newFromRedirectArray() was removed (deprecated in 1.21).
 412 * UserMailer::send() no longer accepts $replyto as the 5th argument and $contentType
 413   as the 6th. These must be passed in the options array now.
 414 * Title::newFromRedirectRecurse() was removed (deprecated in 1.21).
 415
 416 == Compatibility ==
 417
 418 MediaWiki 1.27 requires PHP 5.5.9 or later. There is experimental support for
 419 HHVM 3.6.5 or later.
 420
 421 MySQL is the recommended DBMS. PostgreSQL or SQLite can also be used, but
 422 support for them is somewhat less mature. There is experimental support for
 423 Oracle and Microsoft SQL Server.
 424
 425 The supported versions are:
 426
 427 * MySQL 5.0.3 or later
 428 * PostgreSQL 8.3 or later
 429 * SQLite 3.3.7 or later
 430 * Oracle 9.0.1 or later
 431 * Microsoft SQL Server 2005 (9.00.1399)
 432
 433 == Upgrading ==
 434
 435 1.27 has several database changes since 1.26, and will not work without schema
 436 updates. Note that due to changes to some very large tables like the revision
 437 table, the schema update may take quite long (minutes on a medium sized site,
 438 many hours on a large site).
 439
 440 If upgrading from before 1.11, and you are using a wiki as a commons
 441 repository, make sure that it is updated as well. Otherwise, errors may arise
 442 due to database schema changes.
 443
 444 If upgrading from before 1.7, you may want to run refreshLinks.php to ensure
 445 new database fields are filled with data.
 446
 447 If you are upgrading from MediaWiki 1.4.x or earlier, you should upgrade to
 448 1.5 first. The upgrade script maintenance/upgrade1_5.php has been removed
 449 with MediaWiki 1.21.
 450
 451 Don't forget to always back up your database before upgrading!
 452
 453 See the file UPGRADE for more detailed upgrade instructions.
 454
 455 For notes on 1.26.x and older releases, see HISTORY.
 456
 457 == Online documentation ==
 458
 459 Documentation for both end-users and site administrators is available on
 460 MediaWiki.org, and is covered under the GNU Free Documentation License (except
 461 for pages that explicitly state that their contents are in the public domain):
 462
 463        https://www.mediawiki.org/wiki/Documentation
 464
 465 == Mailing list ==
 466
 467 A mailing list is available for MediaWiki user support and discussion:
 468
 469        https://lists.wikimedia.org/mailman/listinfo/mediawiki-l
 470
 471 A low-traffic announcements-only list is also available:
 472
 473        https://lists.wikimedia.org/mailman/listinfo/mediawiki-announce
 474
 475 It's highly recommended that you sign up for one of these lists if you're
 476 going to run a public MediaWiki, so you can be notified of security fixes.
 477
 478 == IRC help ==
 479
 480 There's usually someone online in #mediawiki on irc.freenode.net.