+* 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".
+* SpecialPageFactory::getList(), deprecated in 1.24, has been removed. You can
+ use ::getNames() instead.
+* 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.
+* ChangeTags::listExtensionActivatedTags and ::listExtensionDefinedTags, deprecated
+ in 1.28, have been removed. Use ::listSoftwareActivatedTags() and
+ ::listSoftwareDefinedTags() instead.