Problems switching Pro Plus Controller for Pro Controller on P4P

I purchased a P4P+ before I discovered it is not compatible with DroneDeploy or just about any 3rd party application. I just purchased a P4P Controller ModelGL300F but am having troubles connecting to the drone. The only thing I can think of is perhaps firmware on the drone that is not compatible with the new controller. My research showed this should work but…

Try following post #17 in this thread exactly.