FDR3 has now been released and is available from here.
FDR3 incorporates many improvements over FDR2, including a multi-core refinement checker (with support for clusters); an integrated type-checker; and a re-imagined user interface. All users of FDR2 and strongly encouraged to upgrade to FDR3 as soon as possible.
FDR2 is no longer available online. If you require a copy of FDR2, please email firstname.lastname@example.org.