You’ll always be able to open older files, and always decrypt and open Premium-encrypted files even if you stop subscribing to Premium.
So, AxCrypt 2 can open any AxCrypt-encrypted file, regardless of whether it’s encrypted with AxCrypt 1 or 2 Free or Premium.
AxCrypt 1 cannot decrypt any file encrypted with AxCrypt 2.
However, right now we don’t have a single “upgrade all files” function so right now if you go Premium files will be upgraded as you go along. We’ll be providing such a function shortly.