I have a Mac Mini with OS 10.6.8, and was wanting to upgrade the OS to a newer version. I'm a bit confused on which version to buy. The Apple App Store has OSX Server for $19.99, but this looks like an add-on for existing mountain lion users. Am I wrong on this, or is there another version of server operating system somewhere out there?
Also, do I have to use a server OS in this model of Mac Mini, or could I just switch to a stand-alone version of OS 10.8? My model has 2.66 GHz, Intel Core 2 Duo, 4 GB 1067 MHz DDR3, dual 500 GB HD's. I don't really use this unit as a server at all, and have almost all of the server features disabled anyway.
You can do everything you like.
If you want to upgrade to OS X Server you will have a stand alone version of Mountain Lion at some point during that process, in order to get OS X Server you need to install Mountain Lion first and thus your server will be a non-server.