The Ubuntu Release Team has announced the availability of new beta test images for select community editions. The new development release, which carries the designation 16.04 Beta 1, is recommended for testers only and is not considered suitable for daily use.
"This beta features images for Lubuntu, Ubuntu Cloud, Ubuntu GNOME, Ubuntu MATE, Ubuntu Kylin, Ubuntu Studioand Xubuntu. Pre-releases of Xenial Xerus are not encouraged for anyone needing a stable system or anyone who is not comfortable running into occasional, even frequent breakage. They are, however, recommended for Ubuntu flavour developers and those who want to help in testing, reporting and fixing bugs as we work towards getting this release ready." Additional information can be found in the release announcement.