Thanks a lot.
I read there are several benefits while using Maria when compared to mysql (speed etc.) but I wanted to be sure Maria will not cause problems with oxid. Based on that I decided to install both.
I think I will continue with mysql now for oxid while using Maria for other stuff where supported and maybe I will swap for Maria later in future Oxid releases when Maria compatibility fully tested and without problems.
Now going to deploy fresh 4.9.11 and connect with mysql backup. Hopefully I will regain functional oxid so I can move forward to 4.10.8 and later finally to 6.x
Is it better to update from 4.10.8 to 6.0.x or I can directly go from 4.10.8 to 6.1.5? Asking in advance, hopefully I will be able to move to 4.10.8 soon.