Apple is dropping support for 32 bit applications on the Mac. As soon as High Sierra 10.13.4 users will start getting warnings of future incompatibility.
No 64-bit port that I know of. I have been having some luck using Furkot.com -- an online trip planner that works quite well, though ther eare inevitable glitches when exporting GPX from it and importing into my zumo 660. But then again, similar issues happen with Basecamp.
