At long last, the U.S. Department of Justice (DOJ) has announced a slew of much-needed policy changes regarding the use of cell-site simulators. Most importantly, starting today all federal law enforcement agencies—and all state and local agencies working with the federal government—will be required to obtain a search warrant supported by probable cause before they are allowed to use cell-site simulators. EFF welcomes these policy changes as long overdue. Colloquially known as “Stingrays” after Harris Corporation’s brand name for a common model,cell-site simulators masquerade as legitimate cell phone towers, tricking phones nearby into connecting to them. This allows agents to learn the unique identifying number for each phone in the area of the device and to track a phone’s location in real time.