+* In User, the cookie-related methods which were wrappers for the functions on the response
+ object, and were deprecated in 1.27, have been removed:
+ * ::setCookie()
+ * ::clearCookie()
+ * ::setExtendedLoginCookie()
+ Note that User::setCookies() remains, and is not deprecated.
+* The global functions wfProfileIn and wfProfileOut, deprecated in 1.25, have been removed.
+* The following methods related to caching of half-parsed HTML were deprecated:
+ * Parser::serializeHalfParsedText()
+ * Parser::unserializeHalfParsedText()
+ * Parser::isValidHalfParsedText()
+ * StripState::getSubState()
+ * StripState::merge()
+* The "free" CSS class is now only applied to unbracketed URLs in wikitext. Links
+ written using square brackets will get the class "text" not "free".
+* OpenSearch::getOpenSearchTemplate(), deprecated in 1.25, has been removed. You
+ can use ApiOpenSearch::getOpenSearchTemplate() instead.
+* The global function wfBaseConvert, deprecated in 1.27, has been removed. Use
+ Wikimedia\base_convert() directly.
+* RFC 157418: Whitespace is trimmed from wikitext headings, wikitext list items,
+ wikitext table captions, wikitext table headings, wikitext table cells. HTML
+ headings, HTML list items, HTML table captions, HTML table headings, HTML table cells
+ will not have this trimming behavior.
+* Calling Database::begin() explicitly during an implicit transaction or when DBO_TRX
+ is set results in an exception. Calling Database::commit() explicitly for an implicit
+ transaction also results in an exception. Previously these were logged as errors.
+ The startAtomic() and endAtomic() methods, or AtomicSectionUpdate should be used
+ instead.
+* The global function wfOutputHandler() was removed, use the its replacement
+ MediaWiki\OutputHandler::handle() instead. The global function was only sometimes defined.
+ Its replacement is always available via the autoloader.