Upgrade from 2015 to 2017

Hi

We currently use ASGRD 2015 and are planning to upgrade to ASGRD 2017. We use a SQL DB to store our connections so a DB upgrade is advised.

Is a DB upgrade mandatory?

I read that ASGRD 2015 & 2017 can be installed side by side. Does that mean ASGRD 2017 can work with a 2015 DB? Or is a 2017 DB backwards compatible and thus works with ASGRD 2015 clients as well?

Unfortunately I don't have a test environment where I could perform these tests myself...

Thanks in advance & kind regards

Shaw