* $wgResourceLoaderExperimentalAsyncLoading was deprecated and removed.
This experimental feature was never enabled by default and is obsolete as of
MediaWiki 1.26, in where ResourceLoader became fully asynchronous.
+* $wgMasterWaitTimeout was removed (deprecated in 1.24).
+* Fields in ParserOptions are now private. Use the accessors instead.
+* Custom LESS functions (defined via $wgResourceLoaderLESSFunctions)
+ have been removed, after being deprecated in 1.24.
=== New features in 1.26 ===
* (T51506) Now action=info gives estimates of actual watchers for a page.
for potentially slow POST requests that need to be as atomic as possible.
* ResourceLoader now loads all scripts asynchronously. The top-queue and
startup modules are no longer synchronously loaded.
+* 'mediawiki.ui.button' styles are no longer unconditionally loaded on every
+ page. During the deprecation period, the styles will only be loaded on pages
+ which contain 'mw-ui-button' in their HTML. Starting in 1.28, the styles will
+ only be loaded if explicitly required.
==== External libraries ====
* Update es5-shim from v4.0.0 to v4.1.5.
* (T53283) load.php sometimes sends 304 response without full headers
* (T65198) Talk page tabs now have a "rel=discussion" attribute
* (T98841) {{msgnw:}} now preserves comments even when subst: is not used.
+* (T104142) $wgEmergencyContact and $wgPasswordSender now use their default
+ value if set to an empty string.
=== Action API changes in 1.26 ===
* New-style continuation is now the default for action=continue. Clients may
information about the relevant block.
=== Action API internal changes in 1.26 ===
+* New metadata item ApiResult::META_KVP_MERGE to allow for merging the KVP key
+ into the value when the value is an assoc.
=== Languages updated in 1.26 ===