I bought my Voyager PE used, and its currently running the 3.3 OS. Do I have to upgrade each version in order, or can I go directly to the latest?
Also, for some reason I only seem to have access to bank B, I’m sure this is some new-user-error on my part . . . any ideas about this?
Mine was on v3.4 when it arrived, because it was showroom stock and had been on a shelf for a while. The process was simple with SysEx Librarian - and I made sure to backup all banks and the existing OS before I started to upload the upgrade.
I’m pretty certain that OS versions are monolithic - i.e. incremental releases don’t need to be overlaid in order. From the way I read it, all versions from v1.5 on may be upgraded in one go. I’d just go for the v3.5 upgrade in one hit on your machine.
Don’t know about your bank problem - are you sure it has the memory upgrade to give it all seven banks? Just having a single bank called “B” is an interesting touch! 
Ig this were the case I would have thought that the single bank version didn’t have bank identifiers at all - just presets. You are of course trying to change banks by holding the cursor button and pressing either up or down arrow buttons?
At the end of the day, I’d back up the whole thing and install v3.5. It may work as planned at that point.
Cool. Very helpful information about the OS. Thanks again.
About the banks 
. . . The manual finally showed today (guy had forgotten to send it with the synth), and it looks like I just didn’t know what I was doing. 
I’m sure it won’t be the last time I ask a silly question though. 