When you open an AxCrypt 1 file with AxCrypt 2, it gets re-encrypted with your new AxCrypt ID password, i.e. the password you set when you created the account.
If you previously shared these files with others, you should upgrade them all to the new AxCrypt 2 software – and then add these account emails to the list of recipient key shares.
AxCrypt 2 has a more sophisticated way to share encrypted files with other. You do not need to share any passwords any more, and every one uses their own one password to AxCrypt.
Instead of using different passwords for different sharing groups of persons, you add the email addresses of the persons you want to share the access to the file with using the key sharing feature.