APPLE INSIDER
Apple has released an update bringing watchOS to version 7.3.1, updating the Apple Watch software two weeks after the last release.
Apple on Monday issued a new update for watchOS 7.3.1 to the public. The update appears to be limited to the Apple Watch Series 5 and Apple Watch SE, fixing a charging issue that can manifest on those models.Users can update watchOS to the latest build by opening the Apple Watch app on their iPhone, tapping My Watch, then General, then Software Update, then Install. Once downloaded, the Apple Watch should be placed on a charger to allow the update to install.
Source: APPLE INSIDER