On three computers, the update installed properly. But stopping then restarting on two, the server is not loading the updated version. Even a Quit is not causing it to install the new server version.
On the third machine, the server had not been set up and running so no stop was necessary, but it also failed to load the new server version when the server was started.
I couldn’t find past references to this part of the update process, but memory is that this is the prescribed way to update the server.
Update: When I manually deleted Panorama Server, then tried to start it, I got this dialog. As a result I remain on b38 for serving.