IPSW Portal

Choose aProduct→Choose aPlatform→Choose aVersion→ClickDownload

Download 5.1 (16R6591) for Apple Watch Series 4 (40mm)

Version:	5.1
Build:	16R6591
Signed:	No
Size:	0.15 GB
Release Date:	2018-10-30 17:21:49
Upload Date:	2018-10-23 01:08:21

Secure download directly from Apple's servers