watchOS 5.1.3 (16S5523a) 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 December 10, 2018 Upload Date December 5, 2018 Filename 6ca24d7715d907e0a136fe1db9fc1055d1ea7ea0.zip Filesize 1.3 GiB Identifier Watch4,1
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