The update also adds irregular heart rhythm notifications where the Watch can help identify conditions like atrial fibrillation. The Apple Watch Series 4 and 5 are the only models compatible with this and ECG but requires individual countries’ health authorities to sign off on its use, hence the addition here of three new regions (the full list of countries is here). 

ECG on the Watch works by placing your finger on the Digital Crown, creating a circuit via electrodes in it and the back of the Watch to take a more detailed heart reading than the heart rate sensor alone.

watchOS 6.2, which is compatible with all Apple Watch models apart from the very first one, also adds in-app purchases for Apple Watch apps and fixes a music playback bug.

Apple also released watchOS 5.3.6 for Apple Watch owners who have an iPhone that can’t run iOS 13.