$wgSharedDB and $wgSharedTables are properly set even on the "central" wiki
that all others are sharing from and that $wgLocalDatabases is set to the
full list of sharing wikis on all those wikis.
+* Massive overhaul to session handling:
+** $wgSessionsInObjectCache is no longer supported and must be true, due to
+ MediaWiki\Session\SessionManager. $wgSessionHandler is similarly no longer
+ used.
+** ObjectCacheSessionHandler is removed, replaced with
+ MediaWiki\Session\PhpSessionHandler.
+** PHP session handling in general ($_SESSION, session_id(), and so on) is
+ deprecated. Use MediaWiki\Session\SessionManager instead. A new config
+ variable, $wgPHPSessionHandling, is available to cause use of $_SESSION to
+ issue a deprecation warning or to cause most PHP session handling to throw
+ exceptions.
+** Deprecated UserSetCookies hook. Session-handling extensions should generally
+ be creating a custom subclass of CookieSessionProvider. Other extensions
+ messing with cookies can no longer count on user data being saved in cookies
+ versus other methods.
+** Deprecated UserLoadFromSession hook, extensions should create a
+ MediaWiki\Session\SessionProvider.
+** The User cannot be loaded from session until after Setup.php completes.
+ Attempts to do so will be ignored and the User will remain unloaded.
+* MediaWiki will now auto-create users as necessary, removing the need for
+ extensions to do so. An 'autocreateaccount' right is added to allow
+ auto-creation when 'createaccount' is not granted to all users.
+* Deprecated AuthPluginAutoCreate hook in favor of LocalUserCreated.
+* Most cookie-handling methods in User are deprecated.
=== New features in 1.27 ===
* $wgDataCenterId and $wgDataCenterRoles where added, which will serve as
from CDN to mitigate DB replication lag and WAN cache purge lag.
* (T49162) Installer will default to setting CACHE_ACCEL as the main cache type
if it is available.
+* It is now possible to patrol file uploads (both for new files and new versions
+ of existing files). Special:NewFiles has gained an option to filter by patrol
+ status. This functionality can be disabled using $wgUseFilePatrol.
+* MediaWiki\Session infrastructure allows for easier use of session mechanisms
+ other than the usual cookies.
+** SessionMetadata and SessionCheckInfo hooks allow for setting and checking
+ custom session metadata.
+* Added MWGrants and associated configuration settings $wgGrantPermissions and
+ $wgGrantPermissionGroups to hold configuration for authentication features
+ such as OAuth that want to allow restricting the user rights a user may make
+ use of.
+** If you're already using the OAuth extension, these new variables are
+ identical to (and will replace) $wgMWOAuthGrantPermissions and
+ $wgMWOAuthGrantPermissionGroups.
+* Added MWRestrictions as a class to check restrictions on a WebRequest, e.g.
+ to assert that the request comes from a particular IP range.
+* Added bot passwords, a rights-restricted login mechanism for API-using bots.
=== External library changes in 1.27 ===
* Added wikimedia/cldr-plural-rule-parser v1.0.0.
* Added wikimedia/relpath v1.0.3.
* Added wikimedia/running-stat v1.1.0.
+* Added wikimedia/php-session-serializer v1.0.3.
==== Removed and replaced external libraries ====
* The following response properties from action=login are deprecated, and may
be removed in the future: lgtoken, cookieprefix, sessionid. Clients should
handle cookies to properly manage session state.
+* action=login transparently allows login using bot passwords. Clients should
+ merely need to change the username and password used after setting up a bot
+ password.
=== Action API internal changes in 1.27 ===
* ApiQueryORM removed.
* Language::armourMath() was removed (deprecated since 1.22).
* LanguageConverter::armourMath() was removed (deprecated since 1.22).
* FakeConverter::armourMath() was removed (deprecated since 1.22).
+* The unused jquery.validate ResourceLoader module was removed.
+* FileRepo::getRootUrl() was removed (deprecated since 1.20).
+* User::generateToken() was removed (deprecated since 1.20).
+* WikiPage::getRawText() was removed (deprecated since 1.21).
== Compatibility ==
MediaWiki 1.27 requires PHP 5.3.3 or later. There is experimental support for
-HHVM 3.3.0.
+HHVM 3.6.5 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