Noticed this with MariaDB.

When using lower than minimum DB version - server/proxy would not start, unless AllowUnsupportedDBVersions=1.

When using higher than maximum DB version - server/proxy will issue a warning, but will start, ignoring AllowUnsupportedDBVersions option.

Steps to reproduce:

Use fresh MariaDB 10.7 rolling release

Result:

Server/Proxy starts normally, just issuing the following warning in the log file:

18138:20220219:131629.016 Unsupported DB! MariaDB version is 100703 which is higher than maximum of 100699

Frontend systeminfo widget also has this warning:

Expected:

Handling "too high" version should work exactly as "too low": do not start unless AllowUnsupportedDBVersions=1.