LMS upgrade procedure on a ReadyNAS Ultra?

I'm told that you don't really need to do a clean install anymore when upgrading LMS on a ReadyNAS, even though various support pages instructs you through a multistep procedure doing so. So it should be possible to keep your preference files I understand. But what is actually necessary to do when upgrading from LMS 7.7.2 to LMS 7.8?

Can I just install my new LMS78 "on top of" the existing LMS772 without stopping the currently running LMS first or clearing its cache? Or do I have to stop the current LMS first and/or clear the cache?

The currently installed LMS772 "plugin" in the ReadyNAS Frontview shows two options besides a Remove button:
1) Delete preference files.
2) Clean cache folder, including media library database, artwork cache etc.
And then there is a warning saying "Please Stop Logitech Media Server before running the cleanup".

In case I need to stop the current LMS first, how do I do that? Can't find that option anywhere? Only way I can think of is to shutdown the NAS, but that makes it a bit complicated to install the new LMS version :-)

What happens if I just choose Remove? Will it stop and remove current install, but keep preference files for use in new LMS78 install?

Yes, I'm a NAS/Linux novice :-)