The Apple Watch Series 4 was introduced on September 12, 2018, and marked a significant redesign with a larger display featuring thinner bezels and curved corners, along with a slightly thinner and rounder chassis.2 It was available in two sizes—40mm and 44mm—and offered in aluminum (silver, space gray, gold) and stainless steel (silver, space black, gold) cases.3 The device featured the S4 chip with a 64-bit dual-core processor, delivering up to twice the performance of its predecessor while maintaining all-day battery life.23 It included a new electrical heart sensor and an ECG app, which received FDA De Novo classification, enabling users to take an electrocardiogram directly from the wrist.23 The Series 4 also introduced fall detection, which uses an improved accelerometer and gyroscope to detect hard falls and can automatically call emergency services if immobility is detected.23

The watch was discontinued on September 10, 2019, after a support lifespan of 5 years and 11 months.2 As of January 2, 2025, Apple added the Apple Watch Series 4 to its vintage products list, meaning it is no longer eligible for new repairs or support, though Apple and its authorized service providers may still offer repairs if parts are available.5 The latest watchOS 11 update dropped support for the Series 4, along with the Series 5 and original Apple Watch SE.5 Despite its age, the Series 4 remains functional for basic smartwatch features such as fitness tracking, notifications, and Apple Pay, though it lacks newer features like always-on display and advanced health sensors found in later models.6 Refurbished units are still available for sale, with prices starting around $98.71 on platforms like eBay.8