Canonical has recently implemented stricter guidelines for the release process of official editions of Ubuntu, such as Lubuntu, Kubuntu, Ubuntu Budgie, Ubuntu Studio, Xubuntu, Ubuntu Kylin, Ubuntu Mate, Ubuntu Unity, Edubuntu, and Ubuntu Cinnamon. The new rules have been put in place to ensure that the editions are adequately prepared for the final release, which will only occur if the beta version is generated on schedule as outlined in the planned timeline. Additionally, any modifications to packages between the beta and final release must be minimal and limited to bug fixes.
/Reports, release notes, official announcements.