FIRMWARE DETAILS

iOS 17.3.1

Build: 21D61Feb 8, 2024Delta OTA

Stable

View details

Filename: b6b5bd7c643843da94b6cf3072b8bd9232416254.zip
File size: 584.3 MB
File type: Delta OTA
Download host: updates.cdn-apple.com
Link availability: Not verified
Source reports active
Last link check: Not checked
SHA-256: 588898f34a4620e5367089f65522b640fd79ed88b74b0da6bb21827386ecbd3b
SHA-1: 9ccbd75c31648841a78cf515dd3abaf88f17382a
Required starting builds: 21C62, 21C66
Board restrictions: Not reported

OTA packages can require an exact starting build and board. A matching hardware identifier alone is not sufficient for installation.

Compatible hardware (1)

iPhone 11 Pro iPhone12,3

Unknown

Signing is specific to the device and file. A signed build does not guarantee a downgrade or successful installation.

Source provenance

AppleDBhttps://api.appledb.dev/ios/iOS%3B21D61.json ↗

MIT — copyright 2022 emiyl
Last imported: Oct 19, 2026, 6:28 PM UTC
Record fingerprint: caa4c3b8f1108221a1cf4826799a13ca