With a nod to the JBridge, I hope upcoming versions of this great software will be available in a 64 Bit format.
I just chatted with someone named Joseph at PG Music. He says Powertracks 2015 will work with Win 8.1 64 bit and Windows 10.
PowerTracks generally follows the feature path of RealBand (minus BIAB-specific features). I suspect that when it comes out, PowerTracks 2016 will include the new RealBand 2016 features minus any BIAB-related features, and so since RealBand 2016 is still 32-bit, PowerTracks 2016 will likewise be 32-bit.