* (bug 40876) Icon for PSD (Adobe Photoshop) file types.
* (bug 40641) Implemented Special:Version/Credits with a list of contributors.
* (bug 7851) Implemented one-click AJAX patrolling.
+* The <data>, <time>, <meta>, and <link> elements are allowed within WikiText
+ for use with Microdata.
+* The HTML5 <mark> tag has been whitelisted.
=== Bug fixes in 1.21 ===
* (bug 40353) SpecialDoubleRedirect should support interwiki redirects.