I replied to a GPUG question earlier today from someone wanting to use SQL 2016 with GP 2015.  It bears repeating here and applies to similar situations as well.

When Microsoft says not compatible, they mean it. It may work, but it’s not supported. If you do run into an issue with compatibility down the road, you have just burned all bridges, since you won’t likely be able to restore it later to a supported SQL version. At that point you can only hope that you’ve kept a copy of databases from the earlier SQL version and reenter everything from that point, or start over. It’s usually a deprecated function is specified in GP coding that will be the problem, and the only fix is to rewrite the software.

For years I was the “Damn the torpedoes, full speed ahead” guy, the one that could always trick the system into making it work after a client broke it, but after seeing the destruction and mayhem it can cause down the road (read potentially hundreds of consulting hours), it’s wise to trust Microsoft’s compatibility list. It’s there for a reason.