watchOS 5.1.3 (16S5535a) for Apple Watch Series 4 (44mm) ✗ 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 8e1f17e917ac762b6daa4d631f494c20ac27b9d4.zip Filesize 1.3 GiB Identifier Watch4,2
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