You can open/decrypt the previously encrypted document(1.x) with the latest version(2.x). Still, you can open/decrypt the old encrypted files with the original file password(which was used in the file encryption process).
AxCrypt 1.x and 2.x are compatible in the sense that 2.x can open all files secured with 1.x. In addition to that, 2.x implements of lot of new rich features, while some functions of 1.x are deprecated. Files secured with AxCrypt 2.x are not possible to open with AxCrypt 1.x. You cannot have both AxCrypt 1.x and 2.x installed at the same time.
AxCrypt will allow the users to decrypt the encrypted file with the original password which is used for encryption.
So please try to remember the file password(which was used in the encryption process) to decrypt/open the old encrypted files.
If you think you almost know the password, we have simple software allowing you to try to find your password, and you can download the most recent version from https://account.axcrypt.net/Download/AxBruteForce.exe and read of how to use it at https://www.axcrypt.net/axcrypt-brute-force/ . Please note that we cannot provide support beyond this.
Still, you are facing any issue, please provide detailed information about the issue and write a mail to firstname.lastname@example.org. We are happy to help you.