watchOS 5.1.2 can be downloaded for free via the Apple Watch app on the iPhone under General -> Software Update. To install the new software, the Apple Watch must have at least 50 percent battery, it must be in a charger and must be within easy reach of the iPhone.
In addition to the ECG function, watchOS 5.1.2 introduces a new feature that notifies you when the Apple Watch detects an abnormal heart rhythm that indicates atrial fibrillation, which may indicate a serious health problem. The ECG feature is limited to Series 4, but irregular heart rhythm notifications are available for all Apple Watch models running watchOS 5 – this is Series 1 or later.
The watchOS 5.1.2 update introduces new complications for the Apple Watch Series 4 infograph dials. Added complications include Email, Messages, Home, Maps, Apple News, My Friends Search, Phone, and Remote Control can now be assigned to the available complication slots on the infograph dial.
For most of these complications, the icon provides quick access to opening an app rather than forwarding information such as unread messages or emails.
watchOS 5.1.2 also includes a new switch in Control Center that allows the walkie-talkie feature to be turned on and off. This makes it easier to disable walkie talkie when it is not in use and turn it back on when needed.
Apple Release Notes:
This update includes new features, enhancements, and fixes:
– New ECG app for Apple Watch Series 4 (US and US only)
* Enables the acquisition of an electrocardiogram similar to a single-channel electrocardiogram
* Can tell if your heart rhythm shows signs of atrial fibrillation (a severe form of irregular heart rhythm) or sinus rhythm, which means your heart is beating in a normal pattern
* Saves the ECG waveform, classification, and any symptoms found in a PDF of the Health app on the iPhone to share with your doctor
– Adds the ability to receive an alert when an irregular heart rhythm is detected that appears to be atrial fibrillation (USA and US only).
– Provides direct access to supported movie tickets, coupons, and reward cards in Wallet when you tap a contactless reader
– Receive notifications and animated celebrations when you reach daily highs during an activity match
– New infographic complications for e-mail, cards, messages, finding friends, home, news, phone, remote
– Manage Control Center Availability for Walkie-Talkie
For more details on the features introduced with the watchOS 5 update released in September, see our watchOS 5 overview