This is a list of known release blockers for Bugzilla Harmony, in prority list order.
MySQL compatibility & checksetup
We can and should only support current and previous releases of MySQL. People coming from MySQL 5.6 or earlier should be nudged to use utf8mb4, which allows for emojis and some obscure languages.
Currently harmony will work with MariaDB 10+ (any version), but will not function in MySQL 8 due to the word "groups" becoming a reserved word.