the list of supported hardware is near the bottom of the preview page https://www.apple.com/macos/monterey-preview/

it's possible tha my rMBP - MacBook Pro (Retina, 15-inch, Mid 2014), 2.5 GHz Quad-Core Intel Core i7, with16 GB 1600 MHz DDR3, NVIDIA GeForce GT 750M/2 GB Intel Iris Pro 1536 MB is not compatible. I was wondering if it would be. I'll update later in the week if it does eventually get th update or not Later.

yep treid that a couple of times but no joy