OpenZFS on OS X

After updating from 2.1.0 to 2.1.6 on Catalina I can't load any of my keys, forcing me to downgrade again to the previous version. Even though I'm absolutely certain I'm entering the correct key it just refuses to load; this is affecting all encrypted datasets across two zpools. I'm using manually entered keys on the command line, and basic encryption settings (aes-256-gcm).

I did not run zpool upgrade on either pool (for fear of being unable to downgrade again). I tried creating a new test pool under 2.1.6 and transferring across one of the smaller datasets, but I couldn't load the key then either, so I wasn't hopeful that upgrading would help.

I was really hoping to upgrade for the faster encryption performance along with various other improvements; please don't tell me my existing 2.1.0 encrypted datasets are unusable with the new version? Is there any way to keep them usable? I'm kind of hosed otherwise because my backups were made using zfs send -w (sending the raw encrypted blocks) so if I can't decrypt then I can't recreate the datasets.

Don't do anything destructive, there is new "compatibility" work from upstream and it looks like we will need to make it better

What does that mean for upgrading though? Has the key format for encryption changed? Is there anything I can do?

It doesn't mean much for upgrading (in terms of your data on disk); just that there are issues with RC1.

There is a new RC2 that was just posted. You can give that a go - RC2 works for me with older 2.1.0/2.1.99 encrypted pools.