redact exception traces and abstract getTrace

[lhc/web/wiklou.git] / RELEASE-NOTES-1.22

Security reminder: MediaWiki does not require PHP's register_globals. If you
have it on, turn it '''off''' if you can.

== MediaWiki 1.22 ==

THIS IS NOT A RELEASE YET

MediaWiki 1.22 is an alpha-quality branch and is not recommended for use in
production.

=== Configuration changes in 1.22 ===
* $wgRedirectScript was removed. It was unused.
* Removed $wgLocalMessageCacheSerialized, it is now always true.
* $wgVectorUseIconWatch is now enabled by default.
* $wgCascadingRestrictionLevels was added.
* ftps, ssh, sftp, xmpp, sip, sips, tel, sms, bitcoin, magnet, urn, and geo
  have been whitelisted inside of $wgUrlProtocols.
* $wgDocType and $wgDTD have been removed and are no longer used for the DOCTYPE.
* $wgHtml5 is no longer used by core. Setting it to false will no longer disable HTML5.
  It is still set to true for extension compatibility but doing so in extensions is deprecated.
* $wgXhtmlDefaultNamespace is no longer used by core. Setting it will no longer change the
  xmlns used by MediaWiki. Reliance on this variable by extensions is deprecated.
* $wgHandheldStyle was removed.
* $wgHandheldForIPhone was removed.
* $wgJsMimeType is no longer used by core. Most usage has been removed since
  HTML output is now exclusively HTML5.
* $wgDBOracleDRCP added. True enables persistent connection with DRCP on Oracle.
* $wgLogAutopatrol added to allow disabling logging of autopatrol edits in the logging table.
  default for $wgLogAutopatrol is true.
* The 'edit' right no longer allows for editing a user's own CSS and JS.
* New rights 'editmyusercss', 'editmyuserjs', 'viewmywatchlist',
  'editmywatchlist', 'viewmyprivateinfo', 'editmyprivateinfo', and
  'editmyoptions' restrict actions that were formerly allowed by default. They
  have been added to the default for $wgGroupPermissions['*'].
* The 'editprotected' right no longer allows bypassing of all page protection
  restrictions. Any group using it for this purpose will now need to have all
  the individual rights listed in $wgRestrictionTypes for the same effect.
* The 'protect' and 'autoconfirmed' rights are no longer used for the default
  page protection levels. The rights 'editprotected' and 'editsemiprotected'
  are now used for this purpose instead.
* (bug 40866) wgOldChangeTagsIndex removed.
* $wgNoFollowDomainExceptions now only matches entire domains. For example,
  an entry for 'bar.com' will still match 'foo.bar.com' but not 'foobar.com'.
* $wgCopyUploadTimeout and $wgCopyUploadAsyncTimeout added to change the timeout times for
  fetching the file during upload by url.
* New key added to $wgGalleryOptions - $wgGalleryOptions['mode'] to set
  default gallery mode.
* New hook 'GalleryGetModes' to allow extensions to make new gallery modes.
* The checkbox for staying in HTTPS displayed on the login form when $wgSecureLogin is
  enabled has been removed. Instead, whether the user stays in HTTPS will be determined
  based on the user's preferences, and whether they came from HTTPS or not.
* $wgRC2UDPAddress, $wgRC2UDPInterwikiPrefix, $wgRC2UDPOmitBots, $wgRC2UDPPort,
  and $wgRC2UDPPrefix configuration options have been deprecated in favor of a
  $wgRCFeeds configuration array. $wgRCFeeds makes both the format and
  destination of recent change notifications customizable, and allows for
  multiple destinations to be specified.
* (bug 53862) portal-url, currentevents-url and helppage have been removed from the
  default Sidebar.
* The 'vector-simplesearch' preference is now enabled by default. Previously
  it was only enabled if the Vector extension was installed.
* The precise format of metric datagrams produced by the UDP profiler and stats counter
  may now be specified as $wgUDPProfilerFormatString and $wgStatsFormatString,
  respectively.
* (bug 54597) $wgBlockOpenProxies, $wgProxyPorts, $wgProxyScriptPath, and
  $wgProxyMemcExpiry have been removed, along with the open proxy scanner
  script they were added for.
* Default value of $wgMaxShellMemory has been tripled (it's now 300 MB).

=== New features in 1.22 ===
* (bug 44525) mediawiki.jqueryMsg can now parse (whitelisted) HTML elements and attributes.
* (bug 33454) Language::sprintfDate now has a timezone parameter, and supports
  the "eIOPTZ" formatting characters.
* EditWarning: A warning is shown when an editor leaves the edit form without
  saving (enabled by default, users can opt-out via the 'useeditwarning'
  preference). This feature was moved from the Vector extension, and is now part
  of core for all skins. Take care when upgrading that you don't use an older
  version of the Vector extension as this feature may conflict.
* New 'mediawiki.ui' CSS module providing mw-ui-* styles for buttons and a
  compact vertical form layout.
* HTMLForm supports a new display format 'vform' which applies this compact vertical
  layout and button styling. Special:PasswordReset uses this format.
* New versions of login (Special:UserLogin) and create account
  (Special:UserLogin/signup) forms using the "vform" compact vertical form layout.
  These forms use new messages that assume a "Help logging in" link, see
  https://www.mediawiki.org/wiki/Manual:Page_customizations;
  https://www.mediawiki.org/wiki/Account_creation_user_experience/Strings lists the
  message key changes.
* (bug 23343) Implemented ability to apply IP blocks to the contents of X-Forwarded-For headers
  by adding a new configuration variable $wgApplyIpBlocksToXff (disabled by default).
* The new hook 'APIGetPossibleErrors' to modify the list of possible errors was
  added.
* (bug 25592) LogEventsList::showLogExtract() will now ignore various
  Pager-related WebRequest parameters by default, as this is overwhelmingly
  likely to be what was intended by users of the method. If any caller wishes
  to use these parameters, the new param 'useRequestParams' may be set to true.
* mw.util.addPortletLink: Tooltip is no longer required to be plain (without
  an accesskey in it already). As such it now rountrips. Creating a link with a
  message as tooltip, grabbing the title attribute and using it to create
  another portlet will work as expected.
* (bug 6747) {{ROOTPAGENAME}} introduced, contains the name of the topmost
  page without namespace.
* BREAKING CHANGE: (bug 41729) Display editsection links next to headings. Also
  change their class name from .editsection to .mw-editsection and place them at
  the end of the heading element instead of the beginning. Client-side code and
  screen-scrapers will have to be adjusted to handle both cases (old HTML will
  still be visible on cached page renders until they are purged); extensions
  using the DoEditSectionLink or EditSectionLink hooks might need adjustments as
  well.
* (bug 45535) introduced the new 'LanguageLinks' hook for manipulating the
  language links associated with a page before display.
* Chosen (http://harvesthq.github.io/chosen/) was added as module 'jquery.chosen'
* HTMLForm will turn multiselect checkboxes into a Chosen interface when setting cssclass 'mw-chosen'
* rebuildLocalisationCache learned --lang option. Let you rebuild l10n caches
  of the specified languages instead of all of them.
* New GetNewMessagesAlert hook allowing extensions to disable or modify the new
  messages alert
* New wgUserNewMsgRevisionId JS global for logged in users. This will be null
  if the user has no new talk page messages. Otherwise it will be set to the
  revision ID of the oldest new talk page message. This will allow gadgets and
  extensions to create their own new message alerts on the client side.
* mediawiki.log: Added log.warn wrapper (uses console.warn and console.trace).
* mediawiki.log: Implemented log.deprecate. This method defines a property and
  uses ES5 getter/setter to emit a warning when they are used.
* $wgCascadingRestrictionLevels was added, allowing one to specify restriction levels
  which can be cascading (previously 'sysop' was hard-coded as the only one).
* XHTML5 support has been improved. If you set $wgMimeType = 'application/xhtml+xml'
  MediaWiki will try outputting markup acording to XHTML5 rules.
* Altered hook 'ProtectionForm::save', adding the reason page protection is
  changed as third parameter.
* New hook 'TitleSquidURLs' for manipulating the list of URLs to be purged from
  HTTP caches when a page is changed.
* Changed the patrolling system to always show the link for patrolling in case the
  current revision is patrollable. This also removed the usage of the rcid URI parameters.
* Oracle DB backend now supports Database Resident Connection Pooling (DRCP).
  Can be enabled by setting $wgDBOracleDRCP=true.
  Requires Oracle DB 11gR1 or above, enabled DRCP inside the DB itself and a
  propper connect string.
  More about DRCP can be found at:
  http://www.oracle-base.com/articles/11g/database-resident-connection-pool-11gr1.php
* Add a new parameter $patrolFooterShown to hook ArticleViewFooter so the hook
  handlers can take further action based on the status of the patrol footer
* A new hook TitleQuickPermissions was added to allow overriding of quick
  permissions in the Title class.
* LinkCache singleton can now be altered or cleared, letting one to specify
  another instance that does not rely on a database backend.
* MediaWiki's PHPUnit tests can now use PHPUnit installed using composer --dev.
* (bug 43689) The lists of templates used on the page and hidden categories it
  is a member of, shown below the edit form, are now collapsible (and collapsed
  by default).
* Parser profiling data, formerly only available in the "NewPP limit report"
  HTML comment, is now also displayed at the bottom of page previews.
* Added ParserLimitReportPrepare and ParserLimitReportFormat hooks, deprecated
  ParserLimitReport hook.
* New user rights have been added to increase granularity in rights management
  for extensions such as OAuth:
** editmyusercss controls whether a user may edit their own CSS subpages.
** editmyuserjs controls whether a user may edit their own JS subpages.
** viewmywatchlist controls whether a user may view their watchlist.
** editmywatchlist controls whether a user may edit their watchlist.
** viewmyprivateinfo controls whether a user may access their private
   information (e.g. registered email address, real name).
** editmyprivateinfo controls whether a user may change their private
   information.
** editmyoptions controls whether a user may change their preferences.
* Add new hook AbortTalkPageEmailNotification, this will be used to determine
  whether to send the regular talk page email notification
* Action classes registered in $wgActions are now also supported in the form of
  a callback (which returns an instance of Action) instead of providing the name
  of a subclass of Action.
* (bug 46513) Vector: Add the collapsibleTabs script from the Vector extension.
* Added $wgRecentChangesFlags for defining new flags for RecentChanges and
  watchlists.
* (bug 40518) mw.toolbar: Implemented mw.toolbar.addButtons for adding multiple
 button objects in one call.
* Rights used for the default protection levels ('sysop' and 'autoconfirmed')
  are now used just for that purpose, instead of overloading other rights. This
  allows easy granting of the ability to edit sysop-protected pages without
  also granting the ability to protect and unprotect.
* (bug 48256) Make brackets in section edit links accessible to CSS.
  They are now wrapped in <span class="mw-editsection-bracket" />.
* (bug 8480) Allow handler specific parameters in galleries (like page number)
* jquery.client: Add detection for Opera 15 and Internet Explorer 11.
* Change tags (used by the AbuseFilter extension) are now shown on diff pages.
* Change tag lists (shown on recent changes, watchlist, user contributions,
  history pages, diff pages) now include a link to Special:Tags to distinguish
  them from edit summaries.
* Added a new method and hook, User::isEveryoneAllowed() and
  UserIsEveryoneAllowed, for use in situations where a "does everyone have this
  right?" check is used to avoid more expensive checks.
* (bug 14431) Display "(No difference)" instead of an empty diff (when comparing
  revisions in the history or when previewing changes while editing).
* New hook 'IsUploadAllowedFromUrl' is added which can be used to intercept uploads by
  URL, useful for blacklisting specific URLs
* (bug 21912) Watchlist token implementation has been refactored and
  Special:ResetTokens was added to allow users to reset their tokens
  instead of presenting them in Preferences.
* Special:PrefixIndex now lets you strip the searched prefix from the displayed
  titles. Given a list of articles named Bug1, Bug2, you can now transclude the
  list of bug numbers using: {{Special:PrefixIndex/Bug|stripprefix=1}}.
  The special page form received a new checkbox matching that option.
* (bug 23580) Implement javascript callback interface "mw.hook".
* (bug 30713) New mw.hook "wikipage.content".
* (bug 40430) jquery.placeholder gets a new parameter to set the attribute value
  to be used.
* $wgHTCPMulticastRouting renamed $wgHTCPRouting since it accepts unicast.
* $wgHTCPRouting rules can now be passed an array of hosts/ports to send purge
  too. Can be used whenever several multicast group could be interested by a
  specific purge.
* (bug 25931) Add Special:RandomInCategory.
* mediawiki.util: addPortletLink now supports passing a jQuery object as nextnode.
* <wbr> can now be used inside WikiText.
* WebResponse::setcookie is much more featureful. Callers using PHP's
  setcookie() or setrawcookie() should begin using this instead.
* New hook WebResponseSetCookie, called from WebResponse::setcookie().
* New hook ResetSessionID, called when the session id is reset.
* Add a mode parameter to <gallery> tag with potential options of "traditional",
  "nolines", "packed", "packed-overlay", or "packed-hover".
* (bug 47399) A success message is now displayed after changing the password.
* Make thumb.php give HTTP redirects for file redirects
* (bug 30607) Special:ListFiles can now show old versions of files. Additionally
  Special:AllMyUploads was introduced so the user can get a list of all things
  they have ever uploaded, even if it was subsequently overriden.
* Introduced Special:MyFiles and Special:AllMyFiles as an alias for Special:MyUploads
  and Special:AllMyUploads respectively.
* IPv6 addresses in X-Forwarded-For headers are now normalised before checking
  against allowed proxy lists.
* Add deferrable update support for callback/closure.
* Add TitleMove hook before page renames.
* Revision deletion backend code is moved out of SpecialRevisiondelete
* Added {{REVISIONSIZE}} variable to get the current size of a revision.
* Add support for the LESS stylesheet language to ResourceLoader. LESS is a
  stylesheet language that compiles into CSS. ResourceLoader file modules may
  include LESS style files; ResourceLoader will compile these files into CSS
  before sending them to the client.
** The $wgResourceLoaderLESSVars configuration variable is an associative array
   mapping variable names to string CSS values. These variables are considered
   declared for all LESS files. Additional variables may be registered by
   adding keys to the array.
** $wgResourceLoaderLESSFunctions is an associative array of custom LESS
   function names to PHP callables. See <http://leafo.net/lessphp/docs/#custom_functions>
   for more details regarding custom functions.
** $wgResourceLoaderLESSImportPaths is an array of file system paths. Files
   referenced in LESS '@import' statements are looked up here first.
* ResourceLoader supports hashes as module cache invalidation trigger (instead
  of or in addition to timestamps).
* Added $wgExtensionEntryPointListFiles for use in mergeMessageFileList.php.
* Added a hook, APIQuerySiteInfoStatisticsInfo, to allow extensions to modify
  the output of the API query meta=siteinfo&siprop=statistics
* Primary keys have been added to both the archive table and the externallinks
  tables.
* Added $wgEnableParserLimitReporting to control whether the NewPP limit report is
  output in a HTML comment.
* The 'UnwatchArticle' and 'WatchArticle' hooks now support a Status object
  instead of just a boolean return value to abort the hook.
* Added a hook, SpecialWatchlistGetNonRevisionTypes, to allow extensions
  with custom recentchanges entries to hook into the Watchlist without 
  clobbering each other.
* A hidden, empty input field was added to the edit form, and any edit that fills
  it in will be rejected. This prevents against the simplest form of spambots.
  Previously in the "SimpleAntiSpam" extension by Ryan Schmidt.
* populateRevisionLength.php maintenance script updated to also populate
  archive.ar_len field.

=== Bug fixes in 1.22 ===
* Disable Special:PasswordReset when $wgEnableEmail is false. Previously one
  could still navigate to the page by entering the URL directly.
* (bug 47138) Fixed a fatal error when a blocked user tries to automatically
  create an account on login due external authentication in some circumstances.
* (bug 23393) HTML <hN> headings containing line breaks are now handled
  correctly.
* (bug 45803) Whitespace within == Headline == syntax and within <hN> headings
  is now non-significant and not preserved in the HTML output.
* (bug 47218) Special:BlockList now handles correctly user names with spaces
  when passed as subpage.
* Pager's properly validate which fields are allowed to be sorted on.
* mw.util.tooltipAccessKeyRegexp: The regex now matches "option-" as well.
  Support for Mac "option" was added in 1.16, but the regex was never updated.
* (bug 46768) Usernames of blocking users now display correctly, even if numeric.
* (bug 39590) Self-transclusions now show the most up to date result always
  after save instead of being a revision behind.
* A bias in wfRandomString() toward digits 1-7 has been corrected. Generated
  strings will now start with digits 0 and 8-f as often as they should.
* (bug 45371) Removed Parser_LinkHooks and CoreLinkFunctions classes.
* (bug 41545) Allow <kbd>, <samp>, and <var> to be nested like allowed in html.
* PLURAL magic word no longer causes a PHP notice when no matching form exists.
* (bug 36641) Patrol page links no longer show on non-existent revisions.
* (bug 35810) Pages not linked from Special:RecentChanges or Special:NewPages
  are patrollable now.
* (bug 30213) JavaScript for search suggestions is now disabled when the API
  is disabled, and AJAX patrolling and watching are now disabled when use of
  the write API is not allowed.
* (bug 48294) API: Fix chunk upload async mode.
* (bug 46749) Broken files tracking category removed from pages if an image
  with that name is uploaded.
* (bug 14176) System messages that are empty were previously incorrectly treated
  as non-existent, causing a fallback to the default. This stopped users from
  overriding system messages to make them blank.
* (bug 48319) action=parse no longer returns an error if passed none of 'oldid',
  'pageid', 'page', 'title', and 'text' (e.g. if only passed 'summary'). A
  warning will instead be issued if 'title' is non-default, unless no props are
  requested.
* Special:Recentchangeslinked will now include upload log entries
* (bug 41281) Fixed ugly output if file size could not be extracted for multi-page media.
* (bug 50315) list=logevents API module will now output log entries by anonymous users.
* (bug 38911) Handle headers with rowspan in jquery.tablesorter
* (bug 658) Converted the table of contents on wiki pages from <table> to <div>
  and adjusted skin CSS accordingly. The CSS was carefully crafted to be
  backwards-compatible in all reasonable cases (uses of the __TOC__ magic word,
  the #toc CSS id and the .toc CSS class). However, particularly bad abuse of
  the id or the class can possibly break.
* CSSJanus now supports rgb, hsl, rgba, and hsla color syntaxes.
* Special:Listfiles can no longer be sorted by image name when filtering
  by user in miser mode.
* (bug 49074) CSSJanus: Handle values of border-radius correctly.
* Handle relative inclusions ({{../name}}) in main namespace with subpages
  enabled correctly (previously MediaWiki tried to include Template:Parent/name
  instead of just Parent/name).
* Added $wgAPIUselessQueryPages to allow extensions to flag their query pages
  for non-inclusion in ApiQueryQueryPages.
* (bug 50870) mediawiki.notification: Notification area should remain visible
  when scrolled down.
* (bug 13438) Special:MIMESearch no longer an expensive special page.
* (bug 48342) Fixed a fatal error when $wgValidateAllHtml is set to true and
  the function apache_request_headers() function is not available.
* (bug 33399) LivePreview: Re-run wikipage content handlers
  (jquery.makeCollapsible, jquery.tablesorter) after preview content is loaded.
* (bug 51891) Fixed PHP notice on Special:PagesWithProp when no properties
  are defined.
* (bug 52006) Corrected documentation of $wgTranscludeCacheExpiry.
* (bug 52077) The APIEditBeforeSave hook is giving the content of the whole
  revision as second argument now, rather than just the current section.
* (bug 49694) $wgSpamRegex is now also applied on the new section headline text
  adding a new topic on a page
* (bug 41756) Improve treatment of multiple comments on a blank line.
* (bug 51064) Purge upstream caches when deleting file assets.
* (bug 39012) File types with a mime that we do not know the extension for
  can no longer be uploaded as an extension that we do know the mime type
  for.
* (bug 51742) Add data-sort-value for better sorting of hitcounts Special:Tags
* (bug 26811) On DB error pages, server hostnames are now hidden when both
  $wgShowHostnames and $wgShowSQLErrors are false.
* (bug 6200) line breaks in <blockquote> are handled like they are in <div>
* (bug 14931) Default character set now set to 'utf8' when a new MySQL
  database is created.
* (bug 47191) Fixed "Column 'si_title' cannot be part of FULLTEXT index"
  MySQL error when installing using the binary character set option.
* (bug 45288) Support mysqli PHP extension
* (bug 55818) BREAKING CHANGE: Removed undocumented 'Debug' hook in wfDebug.
  This resolves an infinite loop when using $wgDebugFunctionEntry = true.

=== API changes in 1.22 ===
* (bug 25553) The JSON output formatter now leaves forward slashes unescaped
  to improve human readability of URLs and similar strings. Also, a "utf8"
  option is now provided to use UTF-8 encoding instead of hex escape codes
  for most non-ASCII characters.
* (bug 46626) xmldoublequote parameter was removed. Because of a bug, the
  parameter has had no effect since MediaWiki 1.16, and so its removal is
  unlikely to impact existing clients.
* (bug 47216) action=query&meta=siteinfo&siprop=skins will now indicate which
  skin is the default and which are unusable (e.g. listed in $wgSkipSkins).
* (bug 25325) Added support for wlshow filtering (bots/anon/minor/patrolled)
  to action=feedwatchlist.
* WDDX formatted output will actually be formatted (and normal output will no
  longer be), and will no longer choke on booleans.
* action=opensearch no longer silently ignores the format parameter.
* action=opensearch now supports format=jsonfm.
* list=usercontribs&ucprop=ids will now include the parent revision id.
* BREAKING CHANGE: action=parse no longer returns all langlinks for the page
  with prop=langlinks by default. The new effectivelanglinks parameter will
  request that the LanguageLinks hook be called to determine the effective
  language links.
* BREAKING CHANGE: list=allpages, list=langbacklinks, and prop=langlinks do not
  apply the new LanguageLinks hook, and thus only consider language links
  stored in the database.
* (bug 47219) Allow specifying change type of Wikipedia feed items
* prop=imageinfo now allows setting iiurlheight without setting iiurlwidth
* prop=info now adds the content model and page language of the title.
* New upload log entries will now contain information on the relevant
  image (sha1 and timestamp).
* (bug 49239) action=parse now can parse in preview and section preview modes.
* (bug 49259) action=patrol now accepts revision ids.
* (bug 48129) list=blocks&bkip= now correctly handles IPv6 CIDR ranges and
  honors $wgBlockCIDRLimit. Note any clients passing invalid values to bkip
  will now receive an error, rather than the previous behavior listing all
  user blocks.
* (bug 48201) action=parse&text=foo now assumes wikitext if no title is given,
  rather than using the content model of the page "API".
* action=watch no longer silently ignores hook abort.
* (bug 50785) action=purge with forcelinkupdate=1 no longer queues refreshLinks
  jobs in the job queue for link table updates of pages that use the given page
  as a template. Instead, forcerecursivelinkupdate=1 is introduced and should
  be used if that behaviour is desirable.
* The 'debugLog' property (enabled by $wgDebugToolbar) no longer sets the log
  entry values through ApiResult::content but directly. This changes the JSON
  output from an array of objects with content in '*' to an array of strings
  with the content.
* (bug 51342) prop=imageinfo iicontinue now contains the dbkey, not the text
  version of the title.
* (bug 52538) action=edit will now use empty text instead of the contents
  of section 0 when passed prependtext or appendtext with section=new.
* Support for the 'gettoken' parameter to action=block and action=unblock,
  deprecated since 1.20, has been removed.
* (bug 49090) Token-getting functions will fail when using jsonp callbacks.
* (bug 52699) action=upload returns normalized file name on warning
  "exists-normalized" instead of filename to be uploaded to.
* (bug 53884) action=edit will now return an error when the specified section
  does not exist in the page.
* Added meta=filerepoinfo API module for getting information about foreign
  file repositories, and related ForeignAPIRepo methods getInfo and getApiUrl.
* The new query module list=allfileusages to enumerate file usages was added.

=== Languages updated in 1.22===

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.

* Batak Toba (bbc-latn) added.
* (bug 46751) Made Buryat (Russia) (буряад) (bxr) fallback to Russian.

=== Other changes in 1.22 ===
* The rc_type field in the recentchanges table has been superseded by a new
  rc_source field.  The rc_source field is a string representation of the
  change type where rc_type was a numeric constant.  This field is not yet
  queried but will be in a future point release of 1.22.  
** Utilize update.php to create and populate this new field.  On larger wiki's
   which do not wish to update recentchanges table in one large update please
   review the sql and comments in maintenance/archives/patch-rc_source.sql.
** The rc_type field of recentchanges will be deprecated in a future point
   release.
* BREAKING CHANGE: Implementation of MediaWiki's JS and JSON value encoding
  has changed:
** MediaWiki no longer supports PHP installations in which the native JSON
   extension is missing or disabled.
** XmlJsCode objects can no longer be nested inside objects or arrays.
   (For Xml::encodeJsCall(), this individually applies to each argument.)
** The sets of characters escaped by default, along with the precise escape
   sequences used, have changed (except for the Xml::escapeJsString()
   function, which is now deprecated).
* BREAKING CHANGE: The Services_JSON class has been removed. If necessary,
  be sure to upgrade affected extensions at the same time (e.g. Collection).
* redirect.php was removed. It was unused.
* ClickTracking integration was dropped from the mediaWiki.user.bucket
  JavaScript function. The 'tracked' option is now ignored.
* BREAKING CHANGE: Legacy skins Simple, MySkin, Chick, Standard and Nostalgia
  were all removed. (Nostalgia was moved to an extension.) The SkinLegacy and
  LegacyTemplate classes that supported them were removed as well and are now a
  part of the Nostalgia extension.
* Event namespace used by jquery.makeCollapsible has been changed from
  'mw-collapse' to 'mw-collapsible' for consistency with the module name.
* BREAKING CHANGE: The "ExternalAuth" authentication subsystem was removed, along
  with its associated globals of $wgExternalAuthType, $wgExternalAuthConf,
  $wgAutocreatePolicy and $wgAllowPrefChange. Affected users are encouraged to
  use AuthPlugin for external authentication/authorization needs.
* The Quickbar feature of the legacy skin model and the last remnants of it
  throughout the code base have been removed.
* Externaledit/externaldiff preference was removed. Very few users used this
  feature, and improper configuration can actually prevent a user from editing
* Calling Linker methods using a skin will now output deprecation warnings.
* (bug 46680) "Return to" links are no longer tagged with rel="next".
* BREAKING CHANGE: mw.util.tooltipAccessKeyRegexp: The match group for the
  accesskey character is now $6 instead of $5.
* HipHop compiler (hphpc) support was removed. HipHop VM support (hhvm) was
  added.
* A new Special:Redirect page was added, providing lookup by revision ID,
  user ID, or file name.  The old Special:Filepath page was reimplemented
  to redirect through Special:Redirect.
* Monobook: Removed the old conditional stylesheets for Opera 6, 7 and 9.
* Support for XHTML 1.0 has been removed. MediaWiki now only outputs (X)HTML5.
* wikibits: User-agent related globals have been deprecated. The following
  properties now default to false and emit mw.log.warn: is_gecko, is_chrome_mac,
  is_chrome, webkit_version, is_safari_win, is_safari, webkit_match, is_ff2,
  ff2_bugs, is_ff2_win, is_ff2_x11, opera95_bugs, opera7_bugs, opera6_bugs,
  is_opera_95, is_opera_preseven, is_opera, and ie6_bugs.
* (bug 48276) MediaWiki will now flash a confirmation message upon successfully
  editing a page.
* (bug 40785) mediawiki.legacy.ajax has been marked as deprecated. The following
  properties now emit mw.log.warn when accessed: sajax_debug, sajax_init_object,
  sajax_do_call and wfSupportsAjax.
* BREAKING CHANGE: meta keywords are no longer supported. A <meta name="keywords"
  will no longer be output and OutputPage::addKeyword no longer exists.
* Methods Title::userCanEditCssSubpage and Title::userCanEditJsSubpage,
  deprecated since 1.19, have been removed.
* (bug 50134) Hook functions are no longer required to return a value. When a
  hook function does not return a value (or when it returns an explicit null),
  processing continues. To abort the hook, a hook function must return an
  explicit, boolean false or a string error message. Other falsey values are
  tantamount to a 'return true' in earlier versions of MediaWiki.
* BREAKING CHANGE: The EditSectionLink hook was removed after being
  deprecated since MediaWiki 1.14. Use DoEditSectionLink instead.
* (bug 48256) The 'editsection-brackets' optional message was removed.
  Section edit links' brackets can now be customized using CSS by
  styling span.mw-editsection-bracket.
* The usePatrol function in ChangesList has been marked as deprecated.
* (bug 50785) A "null edit", that is, a save action in which no changes to the
  page text are made and no revision recorded, will no longer send refreshLinks
  jobs to the job table to update pages which use the edited page as a template.
* The LivePreviewPrepare and LivePreviewDone events triggered on "jQuery( mw )"
  have been deprecated in favour of using mw.hook.
* The 'showjumplinks' user preference has been removed, jump links are now
  always included.
* Methods RecentChange::notifyRC2UDP, RecentChange::sendToUDP, and
  RecentChange::cleanupForIRC have been deprecated, as it is now the
  responsibility of classes implementing the RCFeedFormatter and RCFeedEngine
  interfaces to implement the formatting and delivery for recent change
  notifications.
* SpecialPrefixindex methods namespacePrefixForm() and showPrefixChunk() have
  been made protected. They were accepting form variance arguments, this is now
  using properties in the SpecialPrefixindex class.
* (bug 50310) BREAKING CHANGE: wikibits: Drop support for mwCustomEditButtons.
  It defaults to an empty array and emits mw.log.warn when accessed.
* BREAKING CHANGE: Special:Disambiguations has been removed from MediaWiki core.
  Functions related to disambiguation pages are now handled by the Disambiguator
  extension (https://www.mediawiki.org/wiki/Extension:Disambiguator) (bug
  35981).
* BREAKING CHANGE: The 'mediawiki.legacy.wikiprintable' module has been removed.
  The skins/common/wikiprintable.css file no longer exists. Return value of
  Skin#commonPrintStylesheet is ignored. Please use the 'mediawiki.legacy.commonPrint'
  module instead or base your skin on SkinTemplate.
* (bug 49629) The hook ExtractThumbParamaters has been deprecated in favour
  of media handler overriding MediaHandler::parseParamString.
* (bug 46512) The collapsibleNav feature from the Vector extension has been moved
  to the Vector skin in core.
* SpecialRecentChanges::addRecentChangesJS() function has been renamed
  to addModules() and made protected.
* Methods WatchAction::doWatch and WatchAction::doUnwatch now return a Status
  object instead of a boolean.
* Information boxes (CSS classes errorbox, warningbox, successbox) have been
  made more subtle.
* BREAKING CHANGE: The module 'mediawiki.legacy.IEFixes' has been removed as it was
  unused. The file skins/common/IEFixes.js remains but is only used by wikibits.
  The file never contained any re-usable components. To use it in a skin, load
  'mediawiki.legacy.wikibits' (which IEFixes depends on) and that will import
  IEFixes automatically if user agent conditions are met.

== Compatibility ==

MediaWiki 1.22 requires PHP 5.3.2 or later.

MySQL is the recommended DBMS. PostgreSQL or SQLite can also be used, but
support for them is somewhat less mature. There is experimental support for
Oracle.

The supported versions are:

* MySQL 5.0.2 or later
* PostgreSQL 8.3 or later
* SQLite 3.3.7 or later
* Oracle 9.0.1 or later

== Upgrading ==

1.22 has several database changes since 1.21, and will not work without schema
updates. Note that due to changes to some very large tables like the revision
table, the schema update may take quite long (minutes on a medium sized site,
many hours on a large site).

If upgrading from before 1.11, and you are using a wiki as a commons
repository, make sure that it is updated as well. Otherwise, errors may arise
due to database schema changes.

If upgrading from before 1.7, you may want to run refreshLinks.php to ensure
new database fields are filled with data.

If you are upgrading from MediaWiki 1.4.x or earlier, you should upgrade to
1.5 first. The upgrade script maintenance/upgrade1_5.php has been removed
with MediaWiki 1.21.

Don't forget to always back up your database before upgrading!

See the file UPGRADE for more detailed upgrade instructions.

For notes on 1.21.x and older releases, see HISTORY.

== 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/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.freenode.net.