Hi, Max 2016 is binary compatible with 2015, so you would use FP for Max 2015: just run the setup program as usual, and select the 2016 root folder as target.
Anyway, please note this configuration has not been tested and is not supported. You would find unexpected problems or incompatibilities (specially with third-party renderers as V-Ray).
I suggest (sincerely) you renew the subscription and use the latest FP release.