Drop support for MySQL 5.1? Maybe more?
While reviewing some PRs on the sysadmin docs, it came to my attention that we're currently saying we support MySQL 5.1.3+. MySQL 5.1 has been EOL since 2013. 5.5 went EOL at the end of 2015, with extended support ending this year.
While the impetus to drop support for MySQL isn't as strong as it is for PHP, I think we should consider dropping support before someone reports an issue on an untested configuration and points to the minimum requirements in the docs.
Whether this is just a matter of updating the docs or if we want to set up a check for
MIN_RECOMMENDED_MYSQL_VERSION is something we can discuss. Just updating the docs might be preferable so we don't need to navigate the MySQL/MariaDB/Percona business in code. That said, we should document whether MariaDB/Percona are supported, since we've certainly seen errors particular to one or another.