watchOS 5.1 (16R591) for Apple Watch Series 4 (44mm) ✗ This OTA is not signed. OTA firmwares cannot be restored to. IPSW Downloads collects them for
potential future use. They might also be useful if you're doing research.
Release Date October 30, 2018 Upload Date October 22, 2018 Filename fbc5252629bf2d0e93d89fc0bddd9490f2ccbc26.zip Filesize 1.3 GiB Identifier Watch4,2
All information on these pages is automatically updated. When you click on any Apple Software link on
the site, you are redirected to an Apple server. We do not (and never will) mirror these files. All trademarks are the property of their respective owners. IPSW Downloads is not affiliated with Apple Inc.
© 2026 IPSW Downloads
This page was last modified at 1:25:32 pm UTC on Monday, April 6, 2026 and built at 10:20:22 am UTC on Friday, May 1, 2026.