This release comes with 16 new Flamingo themes adapted from Bootswatch and a new application to manage them. The document index tree and the Navigation panel have been greatly improved by using a new tree widget which is exposed as a wiki macro. The developers will be interested by the new WebJar integration features. This, along with 17 improvements and 33 bug fixes, makes this release worth trying.
Full release notes available at http://www.xwiki.org/xwiki/bin/view/ReleaseNotes/ReleaseNotesXWiki63RC1
See http://jira.xwiki.org/secure/IssueNavigator.jspa?reset=true&jqlQuery=category+in+%28%22Top+Level+Projects%22%29+and+fixVersion+in+%28%22%36.%33-rc-%31%22%29+and+resolution+in+%28%22Fixed%22%29 for more details