On June 21, 2023, the U.S. Food and Drug Administration (“FDA”) issued a warning letter to Zyto Technologies, Inc. (“Zyto”), citing Zyto’s promotion of its Hand Cradle Galvanic Skin Response (“GSR”) device and associated software for uses outside the scope of the device’s 510(k) clearance.[1] This warning letter is one of only a handful issued this year to medical-device manufacturers, and comes shortly after FDA issued a warning letter to iRhythm Technologies, which we wrote about, for touting uses for a remote monitoring device which were, in FDA’s opinion, outside the scope of the product’s 510(k) clearance.[2] These enforcement actions indicate that FDA is keeping a close eye on the promotion of software-enabled medical devices, especially when that promotion suggests a function that has not been approved and/or cleared by FDA for the device.