This is a reference table of major iOS releases and their build numbers, verified directly against Apple's current firmware-signing data rather than pulled from any internal archive. Two things to keep in mind: this list covers major (x.0) releases only, not every point update, and it reflects release history — not what Apple currently allows you to install. Apple stops signing older builds over time, so check current signing status before attempting a restore to any version listed here.
Major iOS Releases: Verified Build Numbers
Build numbers below were verified against live firmware-release data for specific devices. Release dates are shown only where directly confirmed; entries without a specific date are known to the year only.
| Version | Build | Released |
|---|---|---|
| iOS 11.0 | 15A372 | 2017 |
| iOS 12.0 | 16A366 | 2018 |
| iOS 13.0 | 17A577 | 2019 |
| iOS 14.0 | 18A373 | 2020 |
| iOS 15.0 | 19A346 | September 20, 2021 |
| iOS 16.0 | 20A362 | September 12, 2022 |
| iOS 17.0 | 21A329 | September 18, 2023 |
| iOS 18.0 | 22A3354 | September 16, 2024 |
| iOS 26.0 | 23A341 | September 15, 2025 |
| iOS 26.6.1 | 23G83 | August 17, 2026 |
Apple skipped version numbers 19 through 25 in 2025, moving directly from iOS 18 to iOS 26 to align the version number with the release year — that jump is intentional, not a gap in this table.
This is a reference table of major iOS releases and their build numbers, verified directly against Apple's current firmware-signing data rather than pulled from any internal archive. Two things to keep in mind: this list covers major (x.0) releases only, not every point update, and it reflects release history — not what Apple currently allows you to install. Apple stops signing older builds over time, so check current signing status before attempting a restore to any version listed here.
How to Read an iOS Build Number
A build number like 22A3354 breaks down into a version letter tied to the major release, followed by a numeric identifier for that specific build. Point updates (18.0.1, 18.0.2, etc.) get incrementing build numbers within the same letter series, which is how you can tell two builds belong to the same major version at a glance without comparing the marketing version number.
Release History vs. What You Can Actually Install
Every version in the table above shipped and was signed at some point — but Apple only keeps a limited window of builds signed at any given time, usually the current release plus sometimes one version back. A build appearing here does not mean you can restore to it today. Before attempting any restore or downgrade, confirm the exact signing status for your device on our signing status guide, which explains how to check live and what to do if the version you want is no longer signed.
Device-Specific IPSW Guides
Build numbers apply across every compatible device, but the current or final signed version differs by model — older devices stop receiving updates well before newer ones. For your specific model, see:
- iPhone 16 Firmware
- iPhone 15 Firmware
- iPhone 14 Firmware
- iPhone 13 Firmware
- iPhone 12 Firmware
- iPhone 11 Firmware
- iPhone X, XR & XS Firmware
- iPhone SE Firmware
- iPad Firmware
- iPad Pro Firmware
For the newest cycle specifically, see our iOS 27 supported devices list.
iOS Version History FAQ
What does the letter in an iOS build number mean?
It corresponds to the major release series — all builds sharing a letter (like the "22A" in 22A3354) belong to the same major version, iOS 18 in that example.
Why did Apple jump from iOS 18 straight to iOS 26?
In 2025 Apple switched to year-based version numbers across iOS, iPadOS, macOS, watchOS, and tvOS, so the version number matches the year it primarily covers. iOS 19 through 25 were never used.
Does a version appearing in this history mean I can install it now?
No. This table shows release history. Whether a specific build is currently installable depends on whether Apple is still signing it — check our signing status guide for the live picture.
Where can I find every point release, not just major versions?
This page intentionally covers major (x.0) releases only, to keep every listed build number verifiable. Point-release build numbers are covered on the relevant device-specific firmware guide.
