It looks like Apple has updated the algorithm of the Apple Watch Series 4, Series 5, and Series 6 ECG tracking sensors.
Since the Apple Watch Series 4 was released, Apple added an ECG sensor for the smartwatch, which is a test that records the timing and strength of the electrical signals that make a heartbeat. Now with the latest beta of watchOS 7.2, the software algorithm of the sensor is getting updated.
Apple has published a tiny bit of information on its developer website which includes ”version 2” of the algorithm named: “HKAppleECGAlgorithmVersion.version2”. This is mainly to inform developers that there is a new API in the beta software. Apple is widely expected to release iOS 14.3, iPadOS 14.3, and watchOS 7.2 on December 14 to support the upcoming AirPods Max headphones, and Apple Fitness+ service.