I came across a problem recently when trying to back up a Bacula client running bacula-fd version 7.0.5 from a Bacula server running bacual-director / bacula-sd version 5.2.6.
Here are the error messages:
Authorization key rejected by Storage daemon Bad response to Storage command: wanted 2000 OK storage, got 2902 Bad storage
It seemed the older storage daemon was not compatible with newer client.
I installed Bareos client.
Bareos is a fork of Bacula project. Their FAQs informs us that the bareos-fd is compatible with all version of the bacula director when you enable the compatible mode in the config of the file daemon. On Debian and Ubuntu,, installation is straightforward since Bareos packages are available from the software repositories.
apt-get install bareos-client
The installer automatically removes the Bacula client during installation. Now edit the client configuration file (bareos-fd.conf) and make sure Bacula compatibility is on.
compatible = yes
Date: Oct 2016 Client: Operating System: Ubuntu 16.04 Bacula Client: 7.0.5 Bareos Client: 14.2.6-3 Server: Operating System: Debian 8.6 Bacula Storage (PostgreSQL): 5.2.6