Some Apple Watch users who upgrade to the Series 12 or Ultra 4 may temporarily lose access to hypertension notifications due to pending regulatory clearances. Apple's watchOS feature availability page states that Hypertension Notifications may not be available on these devices in certain regions until approvals are completed. The restriction applies to 33 countries and regions, including Canada, Australia, India, Brazil, Singapore, Japan, Taiwan, South Africa, South Korea, and the UAE.

Users in the United States, UK, and EU countries will continue to receive notifications as usual. The Series 12 and Ultra 4 feature revamped sensors, including redesigned optical and electrical heart sensors, larger green LEDs for heart rate monitoring every five seconds, and improved ECG and HRV tracking. These hardware changes necessitate new regulatory approval in some locations.

Apple advises that users relying on hypertension alerts should check availability before upgrading. The delay is attributed to ongoing regulatory processes rather than software limitations.