watchOS 5.1.3 (16S5535a) for Apple Watch Series 4 (40mm) ✗ This OTA is not signed. OTA firmwares cannot be restored to. IPSW Downloads collects them for
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Release Date January 7, 2019 Upload Date January 4, 2019 Filename 53c0ea7bd7f8d44d6ad442a05e9b44dac9e1eb74.zip Filesize 1.3 GiB Identifier Watch4,1
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