Okay I just wanted to write it here to any people who may be curious.
My subsonic is on Ubuntu, and I was upgrading from 5.1 to 5.3. The installation instructions didn't really cover upgrading, so I was worried. But rest assured, yes it is as simple as it seems.
1) Download the deb file
2) dpkg -i the file
3) Relax
That is all I had to do, and I'm just writing this to re-assure anyone else that may forget, yeah, it really is just that easy.
Well, back to my subsonic action!