@davem, you shouldn't have any problems with WHMCS on php7. If you are, then you're likely doing something wrong. What problems are you seeing?
WHMCS is , in ways, better than it used to be. In others (specifically support), it is miles behind where it used to be.
I used to be able to actually *gasp* RELY on support, and getting things fixed quickly.
Now? Well, let's just say that they took a week to get through an upgrade issue, then blamed it on me, instead of their sloppy upgrade code.