Question new plesk installation with mysql 5.1?

[Paris Paraskeva]

trying to setup plesk with mysql 5.1 and php 5.6 on a DO Dropplet. I managed to install plesk 17.8 with but mysql 5.5 was installed and didn't get an option to choose mysql 5.1 although I was opted for different versions of php etc etc so I could select what I needed. Can anyone advise what I need to do in order to setup plesk again with mysql 5.1? I need to setup a DO droplet to support old applications until clients are willing to modernize them, I can not just kill them.