Note* This Tutorial is for ubuntu 64 bit but this process works the same for all systems
Select your OS
Now right click on your version of your server either 64bit or 32bit
Note* if you're unsure of your version then you need to use Putty to login to your server,
once you are logged in you can see your version displayed at the top.
Click "copy link location"
Now use Putty to login to your server
when download is complete type
sudo dpkg -i plexmediaserver_0.9.14.6.1620-e0b7243_amd64.deb
That's how you update your plex server to the lastest version, enjoy!