We will never lock you out of your files due to downgrading of the plan. AxCrypt will continue to work and open any and all AxCrypt-encrypted files regardless of source as long as you know the password. The Premium features will become inactive however, such as the ability to key share (not to receive key shared files, but to originate them), the mobile apps, stronger encryption (but you can always decrypt files even when encrypted with the stronger Premium level encryption) etc.
If I pay for v.2 and at some future date decide to no longer pay, what happens? Will AxCrypt decrypt any files and folders that it has encrypted?
If you stop paying then you downgrade to the free plan.
As Svante has said you’ll lose the premium features but your files won’t suddenly lose protection. AxCrypt won’t decrypt your files unless you ask it to.
It’s not the case that your files will be automatically decrypted because you’ve stopped paying. Therefore if you want to decrypt your files which were encrypted with premium then you’ll still be able to – even as a free user.