The databases, at least for now, are compatible. So you can keep a copy of 0.91.2 on your system, and use that for executing offline transactions.
Unfortunately, it was way too much work to support both formats simultaneously. We had to remove the old one. I recognize that's inconvenient, but we didn't have too many choices in the matter (the new 0.92+ signing system expects different information than was provided by BIP 10 which was used for the old offline tx format).
So the last compatible version is 0.91.2?
That's correct. 0.91.2 is the last version that is compatible with.... every previous version of Armory ever made! yes, I believe it works even if your offline computer is running Armory 0.51 which was like 2.5 years ago. BIP 10 served us well, but it's time to move on.
As I mentioned in other threads, the new format has been pretty thoroughly tested, and we've done 5-way simulfunding and 7-of-7 multisig with it, and it serves our needs. We don't expect to have to change it again, and if we do, we may be able to do so in a backwards-compatible way.
