Overview
- Apple stopped signing iOS 26.6.2 on Monday, September 21, 2026, which means iPhones running iOS 27 can no longer be restored to that iOS 26 build through Apple's verification servers.
- Signing is a server check Apple uses to authorize iOS installs, and an unsigned build fails that check so it cannot be installed or used as a restore image.
- Although Apple released iOS 26.7 last week, it exists only as an over‑the‑air update with no iPhone restore image, so devices already on iOS 27 cannot use 26.7 to downgrade.
- Users who have not upgraded can remain on iOS 26 and can install 26.7 via Settings, but anyone who moves to iOS 27 will have no official rollback path to iOS 26.
- Apple routinely unsigns older builds to reduce exposure to patched security flaws, but the change also means users who experience problems after updating will need Apple to issue a new signed build or fixes rather than rely on a revert.