FreeRADIUS is available from multiple sources:

We highly recommend using the official packages from Network RADIUS, where available.

The documents in this section cover details of the above installation methods, as well as instructions on building packages locally.

These instructions cover installing FreeRADIUS 4.x, which is still in heavy development. Other than exceptional circumstances, you should use version 3.

FreeRADIUS 4 is actively used in multiple high profile client deployments (whom have purchased a support contract from Network RADIUS). It, however, otherwise demands a user that seeks danger and enjoys deploying a highly volatile evolving codebase in environments where traditionally stability is sought. If this describes you, then version 4 is for you! (But don’t come complaining if it breaks.)

Hopefully it is clear, we recommend 99.9%+ of users use FreeRADIUS 3.2.x and the pre-built packages available from Network RADIUS.