Apple Releases watchOS 7.3 With Unity Watch Face, Expanded ECG Availability and More Tuesday January 26, 2021 9:03 am PST by Juli Clover Apple today released watchOS 7.3, the third major update to the watchOS 7 operating system that was released in September. watchOS 7.3 comes more than a month after watchOS 7.2, an update that brought support for Apple Fitness+ The watchOS 7.3 update can be downloaded for free through the dedicated Apple Watch app on the iPhone by going to General > Software Update. To install the new software, the Apple Watch needs to have at least 50 percent battery, it needs to be placed on a charger, and it needs to be in range of the iPhone.