The first release candidate of the 3.4 version brings a few bug fixes and improvements over the previous version. The most notable addition is the possibility to easily import an extension from any repository into XWiki Repository. You can find the full list of issues fixed for this release at http://goo.gl/G9InJ . See http://www.xwiki.org/xwiki/bin/ReleaseNotes/ReleaseNotesXWikiEnterprise34RC1 for more details.
See http://jira.xwiki.org/secure/IssueNavigator.jspa?reset=true&jqlQuery=category+in+%28%22Top+Level+Projects%22%29+and+fixVersion+in+%28%22%33.%34-rc-%31%22%29+and+resolution+in+%28%22Fixed%22%29 for more details