Apple released watchOS 7.3.1 for the Apple Watch Series 5 and SE, and release notes indicated that the update includes a fix to prevent a bug that caused smartwatch models to stop in battery-saving Power Reserve mode.
Apple has published a new support document to supplement watchOS 7.3.1 with additional details on this erro
Power Reserve mode allows you to see the time on your Apple Watch while preserving battery life, but Apple Watch and iPhone do not communicate in Power Reserve mode, nor do you have access to other watch features.
Apple explains in its new support document that a very small number of its smartwatch customers with Series 5 or SE have encountered an issue with their watch not charging after entering Power Reserve mode.
Apple says watchOS 7.3.1, which was released to the public, prevents this issue from occurring with other Series 5 or SE devices
This means that the update won’t solve the problem for users who are already experiencing it, but it should prevent it from happening for additional users.
Very few customers with watchOS 7.2 or watchOS 7.3 Series 5 or SE models have encountered an issue with their watch not charging after entering Power Reserve mode.
To check if your Apple Watch is affected, place your watch on the charger you normally use, then wait at least 30 minutes.
And if your watch suffers from this problem, Apple says: You must contact technical support in order to get the free repair process,The company states that your watch is examined before service to verify its eligibility for free repair.
WatchOS 7.3.1 is a minor update to watchOS 7 that was released in September, and watchOS 7.3.1 comes two weeks after the release of watchOS 7.3.
WatchOS 7.3.1 update can be downloaded for free through the dedicated Apple Watch app on iPhone by going to General option, then Software Update.
To install the new software, the Apple smartwatch must contain at least 50 percent battery, it must be placed on a charger, and it must be within range of the iPhone.
The new update is only available for Series 5 and SE devices, so the update will not be available for other smartwatch models