I get this error on user, system_custom, & cors_config tables.
Specified key was too long; max key length is 767 bytes.
Is mysql 5.6 not officially supported anymore?
After some experimentation I’ve determined it to be the email length of 255. It seems when using a unique constraint and character set of utf8mb4 which is 4 bytes each that you hit the max of 767. So 767/4=191 which works as length for email.
In the other tables they are name & path which need a length of 191.