With a SketchUp Pro subscription are members able to download the newest version of SketchUp and still have workable access to the previous version(s) currently in use?
yes.
you can download and install whatever version you want.
the only limitation is that ONE subscription gives you TWO activations at the same time.
Right now, on my mac, I’m activated on 22 and 23 (because I checked a thing in 22 for someone)
Usually, I’m activated on both my mac and my PC, 23 only.
It’s like the siths, there can only be two at the same time. To access another, you’ll need to log out from one of your activations, or a more radical approach, you can log everyone out directly on SU’s website. like… if you’re far from your computer, and desperately need to access SU pro.