The third variant of Milgrom’s theory (T2) is a relativistic theory. A number of relativistic variants have been proposed. The lack of a unique relativistic theory complicates the generation of testable predictions, but two predictions are only weakly dependent on the form of the relativistic Lagrangian: an early epoch of cosmic reionization, and a particular value for the amplitude ratio of the first and second peaks in the power spectrum of cosmic microwave background (CMB) temperature fluctuations. The first of these two predictions is possibly corroborated, and the second has definitely been confirmed. However, no relativistic version of MOND has yet been proposed that can accurately explain the full CMB spectrum.