It’s not uncommon to see reports of poor battery life after an update to one of Apple’s mobile operating systems. In most cases, these issues die by themselves after the device in question clears the caches or completes index rebuilding. Or sometimes a reboot is needed to resolve the issue. In the most extreme situations, deleting the device and restoring it from backup (or cancel pairing and repair, in the case of the Apple Watch) can make the difference. If you are in such a situation, wait a few days to see if the battery life recovers, and if not, try the restart and reset procedures.
Sometimes, however, the update itself is responsible for the batteries draining faster than they should. This seems to be the case with watchOS 7. Apple has now released watchOS 7.0.2 to fix a bug “that could cause the battery to drain faster”, along with another issue that prevented some users from accessing the ECG the app in regions where it should be available. watchOS 7.0.2 does not include any security updates with published CVE entries, and no other Apple operating systems received updates.
To install the watchOS 7.0.2 update, which was 81 MB for an Apple Watch Series 5, open the Watch app on iPhone and go to My Watch> General> Software Update. It is a quick update, but requires that the watch is on the charger and charged to at least 50%. watchOS 7.0.2 is available for Apple Watch Series 3 and later.
If you have no problems draining the battery or accessing the ECG app, you can postpone the installation of this update until it is convenient within the next week.
Apple’s release notes say nothing about missing Workout GPS routers or health data, but a separate Apple support article suggests a solution if you do not see data that should be there after updating to iOS 14 and watchOS 7. The fix is not difficult, but it will be time consuming – a TidBITS reader suffering from this issue reported that it took approximately 90 minutes. You need to disconnect Apple Watch, make an iCloud backup of iPhone, delete all content and settings from iPhone, and restore both iPhone and Apple Watch from backup.