Not the OP, but I believe they’re talking about the upgrade from 128 bit AES to 256 bit AES. It created some compatibility issues between clients for a few days as the ones that weren’t updated yet couldn’t decrypt the newer 256 AES encrypted notes. That was my experience anyways. It’s a great app/server from my personal experience.
I’ve never had NewPipe present me with a sign in prompt or any not challenges, that’s a very strange scenario to be facing.