I just bought one of those refurbished (new-looking) playbooks at Cowboom and upon turning it on I am prompted to update to version 2.0.1.358. Seems to be no way around it.
Since I read that Dingleberry is still working on jailbrake with seems to work for the older versions, I am hesitant to update and be locked in once the update is installed.
I still have the 2.0 version and haven't updated to the newer one. As far as I know you don't have to update if you don't want to. Every now and then I will get a notification about the current update but I just ignore it. I'm waiting on the new one whenever that one come along!!! BE BOLD!!!