I just switched to Xenial. I can't use mysql 5.7 (have to be slave to a 5.1 server, and 5.7 isn't compatible with 5.1), so I uninstalled it, purged it, then installed MySQL 5.6 from Oracle's download page. All went fine.
Now, though, every time software updater runs, it says it is going to uninstall MySQL 5.6 and put back the MySQL 5.7 that I can't use. I can't do any updates because it won't let me reject only this update! "dpkg-query --list" doesn't show any trace of the old 5.7 MySQL. Why does software updater insist on doing this? How do I make it stop so I can get the rest of the updates?
Thanks.