Comment 24 for bug 2027613

Verification on jammy with version 23.02-0ubuntu1~22.04.2

test 1:
 - installed version 19.12-0ubuntu13
 - registered with Landscape Server
 - service is running:

ubuntu@allowed-beetle:~$ systemctl is-active landscape-client
active

ubuntu@allowed-beetle:~$ pgrep landscape
2276
2277
2278
2279

 - upgraded to version 23.02-0ubuntu1~22.04.2

ubuntu@allowed-beetle:~$ sudo apt install landscape-client
...
Restarting services...
 systemctl restart landscape-client.service
...

expected behaviour: landscape-client service restarts, running the new version (23.02-0ubuntu1~22.04.2)
observed behaviour: landscape-client service restarted, and is running the new version.

ubuntu@allowed-beetle:~$ pgrep landscape
3529
3550
3551
3552

test 2:
 - installed version 19.12-0ubuntu13
 - registered with Landscape Server
 - ran `systemctl stop landscape-client`

ubuntu@flowing-glowworm:~$ sudo systemctl stop landscape-client
ubuntu@flowing-glowworm:~$ pgrep landscape
(no output)

 - upgraded to version 23.02-0ubuntu1~22.04.2

expected behaviour: landscape-client service restarts, running the new version (23.02-0ubuntu1~22.04.2)
observed behaviour: landscape-client service restarted, and is running the new version.

ubuntu@flowing-glowworm:~$ pgrep landscape
3090
3113
3114
3115

test 3:
 - installed version 19.12-0ubuntu13
 - registered with Landscape Server
 - ran `systemctl stop landscape-client`
 - ran `systemctl disable landscape-client`

ubuntu@caring-manatee:~$ sudo systemctl disable landscape-client
Removed /etc/systemd/system/multi-user.target.wants/landscape-client.service.

 - upgraded to version 23.02-0ubuntu1~22.04.2

expected behaviour: landscape-client service does not start (as it is disabled), but when enabled, the new version (23.02-0ubuntu1~22.04.2) is running.
observed behaviour: landscape-client service did not start

ubuntu@caring-manatee:~$ systemctl is-active landscape-client
inactive
ubuntu@caring-manatee:~$ systemctl is-enabled landscape-client
disabled

After systemctl enable and systemctl start landscape-client, it is running the new version.

ubuntu@caring-manatee:~$ sudo systemctl enable landscape-client
Created symlink /etc/systemd/system/multi-user.target.wants/landscape-client.service → /lib/systemd/system/landscape-client.service.
ubuntu@caring-manatee:~$ sudo systemctl start landscape-client
ubuntu@caring-manatee:~$ pgrep landscape
3287
3288
3289
3290

test 4:
 - installed version 19.12-0ubuntu13
 - did not register with Landscape Server
 - service is not running

ubuntu@sacred-buzzard:~$ systemctl is-active landscape-client
inactive
ubuntu@sacred-buzzard:~$ systemctl is-enabled landscape-client
disabled

 - upgraded to version 23.02-0ubuntu1~22.04.2

expected behaviour: landscape-client service never runs, registration has not occurred.
observed behaviour: landscape-client service did not run, registration has not occurred.

ubuntu@sacred-buzzard:~$ systemctl is-active landscape-client
inactive
ubuntu@sacred-buzzard:~$ systemctl is-enabled landscape-client
disabled