I have been using FreeRadius 1.x for a number of years. It has worked just fine. All I am using it for is to authenticate and authorize dial-in users (its about as simple as you can get). The only unusual item is I have a couple of fairly complex modules for authorization and accounting. The question is should I bother to upgrade to 2.x. I don't have a need for any of the new features it provides. I don't even use most of the features in 1.x. My largest concern is the modules. I don't recall seeing anything here about what changes would be required for them other than I believe they have to be compiled with the server. Currently the modules are compiled separately and placed in /usr/local/lib and everything just works.