I tried to update to the new MATE desktop 1.16 but was unable to login after reboot “Unable to start session”.
Used these instructions https://ubuntu-mate.org/blog/mate-desktop-116-for-xenial-xerus/
After wasting some time investigating I ended up reinstalling which was a pain - just a word of caution, I’ll wait for it to appear in the default PPA by which time hopefully it’s fixed.