As it did with the Apple Watch Series 4 and Series 5 with the release of watchOS 9.0, watchOS 9.4 will recalibrate the maximum battery capacity of the 44mm Apple Watch Series 6 to estimate the device’s maximum battery capacity more accurately.
Users can check the health of their Apple Watch battery by opening the Settings app on the wearable, selecting Battery and opening the Battery Health tab.
watchOS 9.4 will only recalibrate the maximum battery capacity of the 44mm Apple Watch Series 6 and not the smaller 40mm model.