MySQL 5.7 and MariaDB 10.2 are quite old, so in 3.1 doc we should deprecate the support for them (using some red, visible border ideally) and in 3.2 LTS - drop it.

It's recommended to make it visible via Blog, slack, etc.

Side note: MySQL 8.0 with PHP 7.3 probably requires a mention that MySQL user should use mysql_native_password plugin, since the 8.0 default - caching_sha2_password is supported since PHP 7.4 only. The following DCL SQL query is gonna create such user:

CREATE USER ezp@localhost IDENTIFIED WITH mysql_native_password BY 'MyPassword123#';