I'm running my remarkable on some ancient software version, and honestly for my use case (reading textbooks and occasional note taking) the old version is perfectly fine.

I don't connect it to the internet, just use the awesome RCU software (paid, but distributed with source code) to move stuff between it and my computer. I presume if I were to try to update it, I'll find the same fate! About exporting, the notebook format is relatively simple, I wrote a very bare-bones software that's able to convert the notebooks to PDF in a few hundred lines of Nim, or you could just use the integrated web UI.