Added function remove_backup() to security_helper.php. Added a call to this from the two places that call check_encryption where the backup is created. Added more defensive code to Config.php to ensure the encrypter objectexists before it is called to avoid a crash.
- automatic upgrade of encryption key.
- automatic decryption of CI3 data, then re-encryption in CI4 and update of table.
- Fixing save function in app_config model