This is the first milestone release of the 8.x cycle. With this occasion we deprecated and retired multiple projects like Colibri Skin, Color Themes, old XWiki 1.0 syntax, etc. We also continued to polish our Nested Pages feature introduced in 7.2, by adding improvements such as: asynchronous copy and rename page actions, improved location picker for simple users and the ability to omit "WebHome" in wiki links syntax.
Full release notes available at http://www.xwiki.org/xwiki/bin/view/ReleaseNotes/ReleaseNotesXWiki80M1
See http://jira.xwiki.org/secure/IssueNavigator.jspa?reset=true&jqlQuery=category+in+%28%22Top+Level+Projects%22%29+and+fixVersion+in+%28%22%38.%30-milestone-%31%22%29+and+resolution+in+%28%22Fixed%22%29 for more details