i just started using this and wasn’t aware that there is a 2.6 version until just now. I have 2.4.1 installed and working fine. Why is 2.6 not on download page? Should I install 2.6? and is there a upgrade only install? How does the upgrade process work?

You haven’t bothered to say what platform you are using. My guess is that you are on OS X, and are using the X11 version of Ardour. We do not plan to issue further updates to the X11 version. Information about the native version is given as noted on the download page. The first truly “public” native OS X release will be out next week, with URLs on the download page. There is no upgrade process - Ardour is a self-contained bundle and you can keep as many different versions around as you wish.