The nature of dark matter is one of the most elusive puzzles in modern physics. With the absence of the discovery of traditional candidates like the WIMP, there has been a strong resurgence of interest in low mass and very light candidates, such as the axion. The Haloscope At Yale Sensitive To Axion CDM (HAYSTAC) is a tunable microwave cavity axion experiment sensitive to significant regions of parameter space interesting to both particle physics and cosmology. In 2017, the HAYSTAC experiment reached sensitivities of order 2x10-14 GeV-1 for axion masses between 23.15 < ma < 24.0 MeV, a mass range previously unexplored by existing haloscope experiments. HAYSTAC is now incorporating a new squeezed-state receiver system and significant upgrades to the cryogenics system, and commissioning for Phase II.