Make sure that your local version is up to date.
The container checks for update on each restart, so to speak, simply restart the container if you want to update it.
BTW I have not seen that there is an update, my server currently tells me this when I issue the info command:
Welcome to Pal Server[v0.1.2.0]
and one player is currently on it playing, so I'm not too sure if there is an update necessary.