Ubuntu's next LTS release is 16.04, which is due for final release on April 21. The final beta was on March 24, and Parallels support is broken with the current Parallels Desktop Pro Edition 11.1.3 (32521). Parallels Tools install, but the machine loses the ability to display the desktop after rebooting. Manually reinstalling Parallels Tools doesn't fix the issue. This happens for Ubuntu upgrades and for fresh Ubuntu installs. Are the Parallels developers currently working with the beta? If not, is there a target release date for LTS support following the final 16.04 release?