The development of High Temperature Superconductor (HTS) dipoles is fundamental for future high magnetic field accelerators. In this context, CERN is currently producing a series of HTS demonstrator dipoles, named FeaTHeR (Five Tesla HTS Research) dipoles. The FeaTHeR-M0 coils are subscale planar racetrack dipoles designed to test fabrication techniques in magnets wound with ReBCO-Roebel cable, and gain experience in quench detection and protection. A set of these demonstrator dipoles will be tested at variable temperature in the 11 T background field of the SULTAN facility. Two upgrades are required in SULTAN for the test of the FeaTHeR dipoles. First, the sample dipoles have to be installed inside a cryostat where the temperature can be regulated between 4.5 and 50 K. The cryostat will be equipped with high current feedthroughs, which can provide more than 10 kA at 50 K to the sample while minimizing the heat leak to the Nb-Ti transformer of SULTAN. The second required upgrade is a counter flow heat exchanger, which will ensure that the warm helium leaving the sample returns to the cryoplant as cold gas at less than 20 K. The construction and commissioning of the new sample cryostat and heat exchanger will be presented along with results of the tests of the first HTS demonstrator dipoles in the SULTAN facility.