path: root/RELEASE-NOTES-1.40

= MediaWiki 1.40 =

== MediaWiki 1.40.0-PRERELEASE ==

THIS IS NOT A RELEASE YET

MediaWiki 1.40 is an alpha-quality development branch, and is not recommended
for use in production.

== Upgrading notes for 1.40 ==
Don't forget to always back up your database before upgrading!

See the file UPGRADE for more detailed per-version upgrade instructions from the
oldest supported upgrading version, MediaWiki 1.35.

Some specific notes for MediaWiki 1.40 upgrades are below:
* Maintenance scripts should now be executed using maintenance/run.php, e.g.
  maintenance/run.php update not maintenance/update.php as before.
* Four extensions have now been bundled with MediaWiki:
  * The Echo extension, which provides a system of user notifications.
  * The Linter extension, which warns about use of deprecated wikitext.
  * The LoginNotify extension, which warns users about failed attempted logins.
  * The Thanks extension, which lets users thank editors for edits.
* The Renameuser extension has been moved to MediaWiki core. It is now possible
  to rename users without installing an extension. The extension had already
  been bundled with MediaWiki since 1.18.

For notes on 1.39.x and older releases, see HISTORY.

=== Configuration changes for system administrators in 1.40 ===
* When computing PBKDF2 password hashes, MediaWiki now detects and uses OpenSSL
  support if available, unless $wgPasswordConfig['pbkdf2']['class'] is set in
  LocalSettings.php. OpenSSL is more efficient, so if that setting is present,
  you should remove it (or set it to 'Pbkdf2PasswordUsingOpenSSL' if possible).
  If users get an internal error when trying to log in, you can try setting it
  to 'Pbkdf2PasswordUsingHashExtension'. In particular, this would be necessary
  if existing PBKDF2 password hashes were computed using a hash algorithm other
  than "sha512" or "sha256" (the current and prior defaults).
* You should configure your webserver to return the http header
  'X-Content-Type-Options: nosniff' for the /images directory. This will
  instruct browsers to not apply content sniffing when accessing the files.
  MediaWiki before 1.40 shipped with a content sniffer which disallowed
  potentially dangerous files at upload time, but this protection has now been
  removed in favor of this 'X-Content-Type-Options: nosniff' header and the
  installer will return a warning when it is not in place.
* Support for MW_USE_LEGACY_DEFAULT_SETTINGS has been removed, setting this
  constant will not have any effect. Use of MW_USE_LEGACY_DEFAULT_SETTINGS
  had been deprecated since 1.39.

==== New configuration ====
* $wgThumbnailNamespaces - This setting lets you define the namespaces for which
  image thumbnails (or a placeholder in the absence of a thumbnail) will be
  displayed on Special:Search.
* $wgResourceLoaderClientPreferences – This experimental flag lets you enable
  client-side preferences for logged-out users.
* $wgExternalLinksSchemaMigrationStage – This temporary flag lets you control
  the migration stage for the new schema for the external links database table.
  Ignore it unless you have a large wiki farm with complex migration needs.
* $wgCommentTempTableSchemaMigrationStage – This temporary flag lets you control
  the migration stage for the temporary comment database table, from revision.
  Ignore it unless you have a large wiki farm with complex migration needs.
* $wgSpecialContributeSkinsEnabled – This setting lets you list skins on which
  Special:Contribute is hidden, for example if they won't work for the feature.

==== Changed configuration ====
* $wgPasswordPolicies – This setting, which controls what makes for a valid
  password for wiki accounts, has been adjusted to raise the minimal password
  length from 1 to 8 characters. The initial limit of 1 has been in place since
  MediaWiki 1.26. If you wish to allow shorter passwords, you can over-ride it
  in your LocalSettings following the guidance on MediaWiki.org.
* (T254045) New accounts can no longer use an equals sign (=) in their
  usernames because of issues it causes in wikitext syntax. This can be
  adjusted by changing the value of $wgInvalidUsernameCharacters.
* (T314318) $wgParserEnableLegacyMediaDOM – This setting has been changed, so
  the alternative modern HTML structure for media is now the default. You can
  disable it for now by over-riding this back to `true` in LocalSettings, but
  this configuration will be removed in future versions of MediaWiki. For more
  details, see the documentation at:
  https://www.mediawiki.org/wiki/Parsoid/Parser_Unification/Media_structure/FAQ
* $wgWatchlistExpiryMaxDuration – This setting, which controls the maximum
  allowed duration for users to set their temporary watchlist entries for expiry
  if that feature is enabled, has been increased from 6 months to 1 year.

==== Removed configuration ====
* $wgShellboxUrl – This setting, deprecated in 1.37, has now been removed; use
  $wgShellboxUrls instead.
* $wgMainWANCache and $wgWANObjectCaches – These never-used settings have been
  removed. To inject WANObjectCache parameters, use $wgWANObjectCache instead.
  These variables were introduced for multi-DC wiki farms to add a separate
  memcached proxy for cross-DC relaying of purges but never used because
  WANObjectCache works based on route prefixes, which can be transparently
  handled by the main memcached proxy.
* $wgParserTestFiles – This setting, deprecated in 1.30, has now been removed;
  extensions can place their parser test files in `tests/parser` instead.
* (T231412) $wgAutoloadAttemptLowercase – This setting, deprecated in 1.35, no
  longer has any effect. If you run into difficulties, fix the names of miscased
  local files.
* (T309787) $wgVerifyMimeTypeIE – This setting, to provide extra security checks
  for very old versions of Internet Explorer clients, was removed. These user
  agents aren't used in practice, and haven't been served JavaScript content for
  years.

=== New user-facing features in 1.40 ===
* Special:Search can now show thumbnails for results for titles outside NS_FILE.
  This is controlled via the new onSearchResultProvideThumbnail hook.
* A new preference ('search-thumbnail-extra-namespaces') to allow users to
  control whether to show more thumbnails (per $wgThumbnailNamespaces)
* (T324910) On pages using multi-content revisions, the raw content of a
  specific slot can be retrieved using the action=raw&slot=<role-name> query
  parameters.
* (T313804) The preferences page now provides a search bar to find preferences,
  regardless of the tab on which they appear.

=== New developer features in 1.40 ===
* The MediaWiki-Docker development environment is now configured to
  run on PHP 8.1 by default, up from PHP 7.4 now that that's EOL.
* Vue development mode is enabled by default in DevelopmentSettings.php
* (T277618) The @noVarDump annotation from the DebugInfoTrait tool can now be
  added to references to stop them from being expanded when their object is
  passed to var_dump(), to make its use for debugging more feasible.
* The ApiSandbox will now by default request responses in the latest API format,
  rather than the original format. Users can set `formatversion` to a different
  value if needed.
* A new hook, GetBlockErrorMessageKeyHook, allows extensions' block error
  messages to be received and displayed by BlockErrorFormatter.
* A new hook, SpecialCreateAccountBenefits, lets extensions and local code set
  custom content on the signup page about the benefits of using an account.
* (T321412) A new 'PageUndeleteComplete' hook has been added for more thorough
  information about a page post restoration than the 'PageUndelete' hook passes.
  This provides similar functionality to the 'PageDeleteComplete' hook.
* The Linker::specialLink() method can now link to a Special page's with a sub-
  page or action parameter set, e.g. [[Special:Contributions/JohnDoe]].
* The PHPUnit entrypoints (tests/phpunit/phpunit.php and vendor/bin/phpunit)
  now check if composer dependencies are up-to-date, like update.php, using
  CheckComposerLockUpToDate. To disable this check, use
  MW_SKIP_EXTERNAL_DEPENDENCIES=1 environment flag when running PHPUnit.
* ManualLogEntry::setForceBotFlag() has been added to allow the forcing of the
  bot flag for log entries which are inserted to the recent changes.

=== External library changes in 1.40 ===

==== New external libraries ====
* Added codex-design-tokens at v0.6.2.
* Added wikimedia/bcp-47-code at v1.0.0.

===== New development-only external libraries =====
* Added wikimedia/langconv at v0.4.2.

==== Changed external libraries ====
* Updated OOUI from v0.44.3 to v0.46.3.
* Updated codex, codex-search, and codex-icons from v0.2.2 to v0.6.2.
* Updated cssjanus/cssjanus from 2.1.0 to 2.1.1.
* Updated guzzlehttp/guzzle 7.4.5 to 7.5.0.
* Updated justinrainbow/json-schema from 5.2.11 to 5.2.12.
* Updated pear/mail from 1.4.1 to 1.5.0.
* Updated pear/net_smtp from 0.10.0 to 0.10.1.
* Updated psr/container from 1.1.1 to 1.1.2.
* Updated symfony/polyfill-php80 from 1.26.0 to 1.27.0.
* Updated symfony/yaml from 5.4.10 to 5.4.17.
* Updated wikimedia/less.php from 3.1.0 to 4.0.0.
* Updated wikimedia/object-factory from 4.0.0 to 5.0.1.
* Updated wikimedia/parsoid from 0.16.0 to 0.17.0.
* Updated wikimedia/remex-html from 3.0.2 to 3.0.3.
* Updated wikimedia/shellbox from 3.0.0 to 4.0.0.
* Updated wikimedia/timestamp from 4.0.0 to 4.1.0.
* Updated wikimedia/xmp-reader from 0.8.4 to 0.9.1.

===== Changed development-only external libraries =====
* Updated QUnit from 2.18.2 to 2.19.4.
* Updated api-testing from 1.5.0 to 1.5.1.
* Updated composer/spdx-licenses from 1.5.6 to 1.5.7.
* Updated eslint-config-wikimedia from 0.22.1 to 0.24.0.
* Updated giorgiosironi/eris from ^0.10.0 to ^0.13.0.
* Updated grunt from 1.5.2 to 1.6.1.
* Updated grunt-banana-checker from 0.9.0 to 0.10.0.
* Updated grunt-eslint from 24.0.0 to 24.0.1.
* Updated karma from 6.3.15 to 6.4.1.
* Updated mediawiki/mediawiki-codesniffer from 38.0.0 to 41.0.0.
* Updated mediawiki/mediawiki-phan-config from 0.11.1 to 0.12.0.
* Updated php-parallel-lint/php-console-highlighter from 0.5 to 1.0.0.
* Updated php-parallel-lint/php-parallel-lint from 1.3.1 to 1.3.2.
* Updated phpunit/phpunit from 8.5.28 to 9.5.28.
* Updated stylelint-config-wikimedia from 0.13.0 to 0.13.1.
* Updated wikimedia/alea from 0.9.3 to 1.0.0.

==== Removed external libraries ====
* jquery.throttle-debounce, deprecated since MediaWiki 1.33.

=== Action API changes in 1.40 ===
* New `cancreateaccount` parameter on action=query&meta=userinfo that allows
  you to check if the user can create an account. Some of the errors that have
  previously been returned by action=query&list=users&usprop=cancreate are now
  returned here.

=== Languages updated in 1.40 ===
MediaWiki supports over 400 languages. Many localisations are updated regularly.
Below only new and removed languages are listed, as well as changes to languages
because of Phabricator reports.

* (T300378) Added language support for Toki Pona (tok).
* (T320465) Added language support for Magahi (mag).
* (T320912) Added language support for Arakanese (rki).
* (T323971) Added language support for Khakas (kjh).
* (T326526) Added language support for Igala (igl).
* (T329476) Added language support for Kusaal (kus).
* (T330266) Added language support for Southern Dagaare (dga).
* (T331596) Added language support for Obolo (ann).
* (T331597) Added language support for Nogai (nog).
* (T331599) Added language support for Wolaytta (wal).
* (T295637) Add no to fallback chain of nb and nn.

=== Breaking changes in 1.40 ===
* OutputPage::enableClientCache no longer accepts a parameter, nor does it
  return the current value. It simply sets the OutputPage::mEnableClientCache
  to true. Use OutputPage::disableClientCache to disable client side caching
  instead.
* ResourceLoader::makeMessageSetScript, unused since 1.26, has been removed
  without deprecation.
* Changes to skins:
  - The internal protected method Skin::getFooterLinks() was removed.
    It had no known usages. Different from SkinTemplate::getFooterLinks.
  - The internal public method Skin::getSiteFooterLinks() was removed.
    It had no known usages.
* The 'oojs-router' module has been removed without deprecation in favour
  of the 'mediawiki.router' wrapper module.
* BagOStuff::makeKeyInternal(), deprecated for public use in 1.36, is now a
  protected method of MediumSpecificBagOStuff.
* WANObjectCache::reap() and WANObjectCache::reapCheckKey(), deprecated since
  1.39, have been removed.
* The EnqueueJob class, unused since 1.31, has been removed without
  deprecation.
* JobQueueGroup::singleton() and ::destroySingletons(), deprecated since 1.37,
  have been removed.
* JobRunner no longer supports manually calling the constructor,
  use MediaWikiServices::getInstance()->getJobRunner() instead.
* JobRunner::setLogger, deprecated since 1.35, has been removed.
* ContextSource::getStats, deprecated since 1.27, has been removed.
* The following public properties of Parser, deprecated in 1.35,
  have been made private: Parser::$mLinkId, Parser::$mIncludeSizes,
  Parser::$mDoubleUnderscore, Parser::$mShowToc, Parser::$mRevisionId,
  Parser::$mRevisionTimestamp, Parser::$mRevisionUser, Parser::$mRevisionSize,
  Parser::$mInputSize, Parser::$mInParse, Parser::$mFirstCall,
  Parser::$mGeneratedPPNodeCount
* The MWGrants class, deprecated since 1.38, has been removed.
* PageProps::getInstance(), deprecated since 1.38, has been removed.
* Global functions wfReadOnly and wfReadOnlyReason, deprecated since 1.38, have
  been removed.
* Global function wfQueriesMustScale, deprecated since 1.39, has been removed.
* Global function wfLogProfilingData, deprecated since 1.38, has been removed.
* The HTMLCacheUpdate class, deprecated since 1.34, has been removed.
* Linker::normaliseSpecialPage(), deprecated since 1.35, has been removed.
* MWTimestamp::getHumanTimestamp(), deprecated since 1.26, has been removed.
* Collation::singleton() and ::factory(), deprecated since 1.37, have been
  removed.
* SpecialVersion::listToText() and SpecialVersion::arrayToString()
  have become private or internal without deprecation.
* The 'ParserTestFiles' key in the schema for extension.json has been removed.
  This was deprecated in 1.30 and the corresponding $wgParserTestFiles
  configuration variable has also been removed in this release.  Extensions
  can put parser test files in their `tests/parser` directory to have them
  automatically run.
* DBLockManager, MySqlLockManager, and PostgreSqlLockManager have been
  removed without deprecation.
* MediaWikiTestCaseTrait::checkPHPExtension() has been removed without
  deprecation. Use PHPUnit @requires annotations instead.
* EditPage::getCopywarn(), deprecated since 1.38, has been removed.
* EditPage::getCopyrightWarning() now requires a MessageLocalizer parameter.
  Use of other parameter types or omitting it was deprecated since 1.38.
* Action constructor now requires Article and IContextSource parameters.
  Use of other parameter types or omitting them was deprecated since 1.35.
* Article::viewRedirect(), deprecated since 1.30, has been removed.
* Title::getNotificationTimestamp(), deprecated since 1.35, has been removed.
* WikiRevision::$fileIsTemp property, deprecated since 1.29, has been removed.
* Use of CommentStore::insertWithTempTable() with 'img_description' is no
  longer supported, it was deprecated since 1.32. Use CommentStore::insert()
  instead.
* Return values in the parameter $pageLang of the PageContentLanguage hook with
  other types than a Language object, deprecated since 1.33 & emitting warnings
  since 1.38, now throws an exception.
* FormatMetadata::flattenArrayContentLang(), deprecated since 1.36, has been
  removed.
* WikiRevision::downloadSource() and ::importUpload(), deprecated since 1.31,
  have been removed.
* DataUpdate::runUpdates(), deprecated since 1.28, has been removed.
* CdnCacheUpdate::newFromTitles(), deprecated since 1.35, has been removed.
* HtmlFileCacheUpdate::newFromTitles(), deprecated since 1.37, has been
  removed.
* BaseTemplate::renderAfterPortlet() and ::getAfterPortlet(), has been removed.
  Use the corresponding methods in Skin class.
* DifferenceEngine::textDiff(), deprecated since 1.32, has been removed.
* Skin::getSearchPageTitle() and Skin::setSearchPageTitle(), deprecated since
  1.38, have been removed.
* DifferenceEngine::getDiffBodyCacheKey(), deprecated since 1.31, has been
  removed.
* ForeignDBViaLBRepo::getMasterDB(), LocalRepo::getMasterDB(), and
  JobQueueDB::getMasterDB(), deprecated since 1.37, have been removed.
* Clarified that the InitializeArticleMaybeRedirect hook should not change
  its $article parameter; the behavior when doing so was previously
  undocumented.
* IDatabase::ping()'s $rtt parameter was removed without deprecation.
* IDatabase::setBigSelects(), unused, was removed without deprecation.
* IDatabase::attributesFromType(), unused, was removed without deprecation.
* IMaintainableDatabase::deadlockLoop() was removed without deprecation.
* DatabasePostgres::remappedTableName(), deprecated since 1.37, has been
  removed.
* ILBFactory::getChronologyProtectorClientId and ::commitAll, unused, were
   removed without deprecation.
* LoadBalancer::haveIndex() and ::isNonZeroLoad(), deprecated in 1.34,
  have been removed.
* LoadBalancer::getLazyConnectionRef(), deprecated in 1.38, has been removed.
* ILBFactory::forEachLB(), deprecated in 1.39, has been removed.
* LoadBalancer::getTransactionRoundStage and ::commitAll, unused, were
  removed without deprecation.
* ILoadBalancer::getLaggedReplicaMode, unused, was removed  without
  deprecation. Use ILBFactory::laggedReplicaUsed() instead.
* Optional parameters of ILoadBalancer::waitForPrimaryPos(), $pos and $timeout
  have been removed without deprecation as they are unused.
* LoadMonitorMysql was removed without deprecation. Use LoadMonitor instead.
* IDatabase::selectDB(), deprecated since 1.32, has been removed.
  Use IDatabase::selectDomain() instead.
* The following deprecated hooks have been removed:
  - BaseTemplateAfterPortlet, deprecated in 1.35
  - BeforeParserFetchTemplateAndtitle, deprecated in 1.36
  - BeforeParserrenderImageGallery, deprecated in 1.35
  - InternalParseBeforeSanitize, deprecated in 1.35
  - LinksUpdateConstructed, deprecated in 1.38
  - LinksUpdateAfterInsert, deprecated in 1.38
  - ParserSectionCreate, deprecated in 1.35
  - ResourceLoaderTestModules, deprecated in 1.33
  - SpecialMuteSubmit, deprecated in 1.35
  - UserLoadFromDatabase, deprecated in 1.37
  - UserSetCookies, deprecated in 1.27
* RemexDriver::__construct() now only accepts a ServiceOptions instance as
  the only argument. Passing an array was deprecated since 1.36.
* TidyDriverBase::supportsValidate(), deprecated since 1.36, has been removed.
* RevDelList::reloadFromMaster(), deprecated since 1.37, has been removed.
* ExternalStoreDB::getMaster(), deprecated since 1.37, has been removed.
* DeletePage::deletionWasScheduled(), deprecated since 1.38, has been removed.
* The SearchResultProvideThumbnailHook (which was unstable) and now no longer
  used, has been removed. Use SearchResultProvideThumbnailHook in the search
  namespace: MediaWiki\Search\Hook\SearchResultProvideThumbnailHook.
* Command::cgroup(), deprecated since 1.36, has been removed.
* When running tests, the serialize_precision INI setting is now set to -1
  (current PHP default) instead of 17. Extension tests may need to be adjusted
  accordingly; string representations of floating-point numbers in serialized
  or JSON-encoded data may change.
* WikiRevision::$sha1base36 is now private.
* IcuCollation::getUnicodeVersionForICU() was removed without deprecation.
* LinkFilter::supportsIDN() was removed without deprecation.
* The ability to pass null for the errorData parameter of HttpException and
  LocalizedHttpException was removed without deprecation.
* ApiQueryExtLinksUsage::getProtocolPrefix() and ::prepareProtocols() have
  been moved to LinkFilter with the same name.
* .box-sizing() Less mixin, deprecated since 1.37, has been removed.
  Use CSS box-sizing now.
* MimeAnalyzer::getIEMimeTypes() and IEContentAnalyzer were removed.
* Language::commafy and mw.language.commafy, deprecated since 1.36, has been
  removed.
* BagOStuff::decr(), deprecated since 1.28, has been removed.
* BagOStuff::incr(), deprecated since 1.28, has been removed.

=== Deprecations in 1.40 ===
* Changes to skins:
  - The public Skin::footerLink is deprecated.
    Use SkinComponentMenuLink::getTemplateData instead.
    It now emits deprecation warnings.
  - The protected Skin::lastModified is deprecated, and marked for @internal use
    and now emits deprecation warnings.
* Manipulating $wgHooks after initialization is deprecated.
  HookContainer::register() or HookContainer::scopedRegister() should be
  used instead. During initialization, SettingsBuilder::registerHookHandlers
  can be used. For backwards compatibility, $wgHooks is replaced by a fake
  array that calls methods on HookContainer. $wgHooks can still be used as a
  configuration variable, only dynamic manipulation is deprecated.
* ParserOptions::{get,set}ExternalLinkTarget() and
  ParserOptions::{get,set}MaxTemplateDepth() have been deprecated and marked
  for @internal use only.
* ParserOutput::getCategories() has been deprecated; use ::getCategoryNames()
  and ::getCategorySortKey() instead.
* ParserOutput::{get,set}TOCHTML() has been deprecated; use
  ::{get,set}TOCData() instead.
* TransactionProfiler::setSilenced() is deprecated.
  Use TransactionProfiler::silenceForScope() instead.
* The following methods in the Title class, deprecated since 1.37, emits
  deprecations warnings:
  - ::areCascadeProtectionSourcesLoaded()
  - ::areRestrictionsCascading()
  - ::areRestrictionsLoaded()
  - ::getAllRestrictions()
  - ::getCascadeProtectionSources()
  - ::getFilteredRestrictionTypes()
  - ::getRestrictionExpiry()
  - ::getRestrictionTypes()
  - ::getRestrictions()
  - ::isCascadeProtected()
  - ::isProtected()
  - ::isSemiProtected()
  - ::loadRestrictionsFromRows()
* The class Pbkdf2Password was renamed to Pbkdf2PasswordUsingHashExtension,
  and the old name is now deprecated.
* WikiPage::factory(), ::newFromID() and ::newFromRow, deprecated in 1.36, now
  emit deprecation warnings.
* Manually constructing a LinkBatch object, deprecated in 1.35, now emits
  deprecation warnings. Use LinkBatchFactory instead.
* Calling MediaWikiSite::getFileUrl() without a $path argument is deprecated.
  If you need the "generic" full file path, with $1 not replaced by anything,
  call $site->getPath( MediaWikiSite::PATH_FILE ) directly.
* In SessionConsistentConnectionManager, the methods
  getReadConnectionRef() and getWriteConnectionRef() are deprecated;
  the ConnectionManager methods they override had been deprecated already.
* Database::wasErrorReissuable() is deprecated.
* MimeAnalyzer::isPHPImageType was not used and will now emit deprecation
  warnings.
* Parser::getFunctionLang() has been deprecated; use
  Parser::getTargetLanguage() instead.
* MagicWordArray::getVariableRegex(), deprecated in 1.36, now emits deprecation
  warnings.
* AbstractBlock::getId() now emits deprecation warnings in case of cross-wiki
  access. This use was deprecated in 1.38.
* CommentStore::getStore, deprecated in 1.31, now emits deprecation warnings.
* BacklinkCache::get(), ::getLinks() and ::getCascadeProtectedLinks(),
  deprecated in 1.37, now emit deprecation warnings.
* LanguageConverterFactory::isTitleConversionDisabled(), deprecated in 1.36,
  now emits deprecation warnings.
* Language::getFileName(), ::getMessagesFileName() and
  ::getJsonMessagesFileName(), deprecated in 1.34,
  now emit deprecation warnings.
* Language::getLocalisationCache(), deprecated in 1.34, also
  Language::getMessagesFor(), ::getMessageFor() and ::getMessageKeysFor(),
  deprecated in 1.35, now emit deprecation warnings.
* User::incEditCount(), deprecated in 1.37, now emits deprecation warnings.
* User::idFromName(), deprecated in 1.37, now emits deprecation warnings.
* The ability to override and use User::$mRights, deprecated in 1.34, now emits
  deprecation warnings.
* IndexPager::getHookContainer is deprecated and emits deprecation warnings.
  Inject a HookContainer instead.
* User::getGroupPermissions(), ::getGroupsWithPermission() and
  ::groupHasPermission(), deprecated in 1.34, now emit deprecation warnings.
* PermissionManager::getGroupPermissions(), ::getGroupsWithPermission() and
  ::groupHasPermission(), deprecated in 1.36, now emit deprecation warnings.
* Global function wfShowingResults is deprecated and emits deprecation warnings.
* UserGroupMembership::getGroupMemberName is deprecated, the deprecation of
  UserGroupMembership::getGroupName in 1.38 missed a release note.
  Use Language::getGroupMemberName or ::getGroupName instead.
* AbstractBlock::getPermissionsError(), deprecated in 1.35, now emits
  deprecation warnings.
* SearchEngine::getNearMatcher() and ::getDefaultMatcher() have been deprecated
  in favor of MediaWikiServices::getInstance()->getTitleMatcher().
* SearchNearMatcher class has been deprecated in 1.40 in favor of TitleMatcher.
* The following functions are deprecated: User::isBlockedGlobally and
  User::getGlobalBlock. Use User::getBlock instead.
* The UserIsBlockedGlobally hook is deprecated.
  Use GetUserBlock hook instead.
* The SystemBlock type global-block is deprecated.
  GlobalBlocks are now added into CompositeBlocks via the GetUserBlock hook.
* Language::isWellFormedLanguageTag(), deprecated in 1.39, now emits deprecation
  notices. Please use LanguageCode::isWellFormedLanguageTag() instead.
* Language::fetchLanguageNames() and ::fetchLanguageName(), deprecated in 1.34,
  now emit deprecation warnings.
* Language::getFallbackFor(), ::getFallbacksIncludingSiteLanguage() and
  ::getFallbacksFor(), deprecated in 1.35, now emit deprecation warnings.
* Language::isSupportedLanguage(), ::isValidCode(), ::isValidBuiltInCode() and
  ::isKnownLanguageTag(), deprecated in 1.34, now emit deprecation warnings.
* Language::getConverter(), ::autoConvert(), ::autoConvertToAllVariants(),
  ::convert(), ::convertNamespace(), ::convertHtml(), ::convertCategoryKey(),
  ::getVariants(), ::hasVariants(), ::hasVariant(), ::getDefaultVariant(),
  ::getURLVariant(), ::getExtraHashOptions(), ::getConvRuleTitle(),
  deprecated in 1.35, now emit deprecation warnings.
* Language::factory() and ::getParentLanguage(), deprecated in 1.35, now emit
  deprecation warnings.
* Executing maintenance scripts directly is deprecated. The maintenance/run.php
  entry point should be used instead.
* MWHttpRequest::factory, deprecated in 1.34, now emits deprecation warnings.
* Job::factory is deprecated, use JobFactory::newJob instead.
* Http::request(), ::get(), ::post(), ::userAgent() and ::isValidURI(),
  deprecated in 1.34, now emit deprecation warnings.
* Title.js's confusingly-named getName() and getNameText() methods, for using
  media files' pages, have been renamed to getFileNameWithoutExtension() and
  getFileNameTextWithoutExtension() respectively. The old names are deprecated.
* Command::whitelistPaths() should now emit deprecation warnings. Make use of
  Command::allowPaths/disallowPaths() instead.
* When manually creating an HTMLFormField (i.e. not via HTMLForm::factory),
  it is deprecated to not include the "parent" field as one of the parameters.
* The MWException class is deprecated. Use native exceptions, either directly
  or as base classes.
* SelectQueryBuilder::lockForUpdate() is deprecated. Use ::forUpdate() with
  ::fetchRowCount() or ::acquireRowLocks() instead.
* ArticleUndelete hook is deprecated. Use PageUndeleteComplete hook instead.
* The global function wfReportTime() is now deprecated.
* PrevNextNavigationRenderer, deprecated in 1.39, now emits deprecation
  warnings.
* PagerNavigationBuilder::setMakeLinkCallback(), deprecated in 1.39, now emits
  deprecation warnings.
* IndexPager::getPagingLinks(), IndexPager::getLimitLinks() and
  IndexPager::buildPrevNextNavigation(), deprecated in 1.39, now emit
  deprecation warnings.
* Overriding the method IndexPager::makeLink(), deprecated in 1.39, now emits
  deprecation warnings.
* The following class names were namespaced (and, for the special pages,
  also renamed), and the old class names are now deprecated:
  - MostimagesPage -> MediaWiki\Specials\SpecialMostImages
  - MovePageForm -> MediaWiki\Specials\SpecialMovePage
  - UserrightsPage -> MediaWiki\Specials\SpecialUserRights
  - WantedFilesPage -> MediaWiki\Specials\SpecialWantedFiles
  - WantedPagesPage -> MediaWiki\Specials\SpecialWantedPages
  - DerivativeRequest -> MediaWiki\Request\DerivativeRequest
  - FauxRequest -> MediaWiki\Request\FauxRequest
  - FauxRequestUpload -> MediaWiki\Request\FauxRequestUpload
  - PathRouter -> MediaWiki\Request\PathRouter
  - WebRequestUpload -> MediaWiki\Request\WebRequestUpload
  - HeaderCallback -> MediaWiki\Request\HeaderCallback
  - FauxResponse -> MediaWiki\Request\FauxResponse
  - WebResponse -> MediaWiki\Request\WebResponse
  - ForeignResourceManager ->
    MediaWiki\ResourceLoader\ForeignResourceManager
  - DummyLinker -> MediaWiki\Linker\DummyLinker
  - Linker -> MediaWiki\Linker\Linker
  - PageProps -> MediaWiki\Page\PageProps
  - MagicWord -> MediaWiki\Parser\MagicWord
  - MagicWordArray -> MediaWiki\Parser\MagicWordArray
  - MagicWordFactory -> MediaWiki\Parser\MagicWordFactory
  - RawMessage -> MediaWiki\Language\RawMessage
  - ActorMigration -> MediaWiki\User\ActorMigration
  - ActorMigrationBase -> MediaWiki\User\ActorMigrationBase
  - CategoriesRdf -> MediaWiki\Category\CategoriesRdf
  - Category -> MediaWiki\Category\Category
  - CategoryViewer -> MediaWiki\Category\CategoryViewer
  - TrackingCategories -> MediaWiki\Category\TrackingCategories
  - EditPage -> MediaWiki\EditPage\EditPage
  - TemplatesOnThisPageFormatter ->
    MediaWiki\EditPage\TemplatesOnThisPageFormatter
  - ContentSecurityPolicy -> MediaWiki\Request\ContentSecurityPolicy
  - FormOptions -> MediaWiki\Html\FormOptions
  - Html -> MediaWiki\Html\Html
  - HtmlHelper -> MediaWiki\Html\HtmlHelper
  - TemplateParser -> MediaWiki\Html\TemplateParser
  - FormOptions -> MediaWiki\Html\FormOptions
  - WikiMap -> MediaWiki\WikiMap\WikiMap
  - WikiReference -> MediaWiki\WikiMap\WikiReference
  - MediaWiki\BadFileLookup -> MediaWiki\Page\File\BadFileLookup
  - FileDeleteForm -> Mediawiki\Page\File\FileDeleteForm
  - MergeHistory -> Mediawiki\Page\MergeHistory
  - MovePage -> Mediawiki\Page\MovePage
  - ProtectionForm -> MediaWiki\Page\ProtectionForm
  - LinkFilter -> MediaWiki\ExternalLinks\LinkFilter
  - TitleArray -> MediaWiki\Title\TitleArray
  - TitleArrayFromResult -> MediaWiki\Title\TitleArrayFromResult
  - TitleFactory -> MediaWiki\Title\TitleFactory
  - Title -> MediaWiki\Title\Title
  - ForkController -> MediaWiki\Maintenance\ForkController
  - OrderedStreamingForkController ->
    MediaWiki\Maintenance\OrderedStreamingForkController
  - AtomFeed -> MediaWiki\Feed\AtomFeed
  - ChannelFeed -> MediaWiki\Feed\ChannelFeed
  - FeedItem -> MediaWiki\Feed\FeedItem
  - FeedUtils -> MediaWiki\Feed\FeedUtils
  - RSSFeed -> MediaWiki\Feed\RSSFeed
  - DeprecatedGlobal -> MediaWiki\StubObject\DeprecatedGlobal
  - StubGlobalUser -> MediaWiki\StubObject\StubGlobalUser
  - StubObject -> MediaWiki\StubObject\StubObject
  - StubUserLang -> MediaWiki\StubObject\StubUserLang
* ContentHandler::getParserOutputForIndexing() and ::getDataForSearchIndex()
  now take an optional RevisionRecord parameter.
* The SearchDataForIndex hook is deprecated in favor of SearchDataForIndex2
* IDatabase::lastQuery and IReadableDatabase::lastQuery are deprecated without
  without replacement.

=== Other changes in 1.40 ===
* Calling RecentChange::doMarkPatrolled() with $auto = true has no effect and
  logs a warning. Since 1.31, it would mark the change as manually patrolled,
  but would not log it as such in patrol log and would still require
  'autopatrol' right (not 'patrol'). Generally, whether a change should become
  autopatrolled, is usually determined before it's inserted in the database.
* In versions of MediaWiki before 1.39, the table of contents location
  was marked internally with <mw:toc>...</mw:toc>; in version 1.39
  this was changed to an empty tag <mw:tocplace />.  In 1.40 this has
  been changed a final time to use an empty <meta> tag for future
  Parsoid compatibility (see Parser::TOC_PLACEHOLDER).  This may
  affect you if stale content is left in the ParserCache or if your
  skin did manual ToC replacement without using the recommended
  Parser::replaceTableOfContentsMarker() function.
* Skins can now choose which Codex theme should be loaded by setting the
  SkinCodexThemes attribute in their skin.json file.
* The parser test framework has been updated, and the 'pst', 'ill', 'cat'
  and 'showflags' options have slight differences in their output.  These
  options are not much used outside core, but third parties may need to
  update parser tests.

== Compatibility ==

MediaWiki 1.40 requires PHP 7.4.3 or later and the following PHP extensions:

* ctype
* dom
* fileinfo
* iconv
* intl
* json
* mbstring
* xml

MariaDB is the recommended database software. MySQL, PostgreSQL, or SQLite can
be used instead, but support for them is somewhat less mature.

The supported versions are:

* MariaDB 10.3 or higher
* MySQL 5.7.0 or higher
* PostgreSQL 10 or later
* SQLite 3.8.0 or later

== Online documentation ==
Documentation for both end-users and site administrators is available on
MediaWiki.org, and is covered under the GNU Free Documentation License (except
for pages that explicitly state that their contents are in the public domain):

       https://www.mediawiki.org/wiki/Special:MyLanguage/Documentation

== Mailing list ==
A mailing list is available for MediaWiki user support and discussion:

       https://lists.wikimedia.org/mailman/listinfo/mediawiki-l

A low-traffic announcements-only list is also available:

       https://lists.wikimedia.org/mailman/listinfo/mediawiki-announce

It's highly recommended that you sign up for one of these lists if you're
going to run a public MediaWiki, so you can be notified of security fixes.

== IRC help ==
There's usually someone online in #mediawiki on irc.libera.chat.