Choose aProduct→Choose aPlatform→Choose aVersion→ClickDownload

Download 13.3.1 (17D50) for iPhone 6s

Version:	13.3.1
Build:	17D50
Signed:	No
Size:	3.46 GB
Release Date:	2020-01-28 18:02:44
Upload Date:	2020-01-22 01:01:48
SHA1:	90941bd17d68ba09d3719ca96f75c6038ff65c08
MD5:	d955380242e4851f35ee6b2197fa1e07
SHA256:	e31085f1601e0dd9d0dfea6a021407de70f94b904fabaa9f2137a276c63e159c

Secure download directly from Apple's servers

IPSW Portal