The iOS 26.4.1 update released today fixes a significant bug in iCloud synchronization. The bug affected the Apple Passwords app, third-party apps, and all services based on CloudKit.
Apple's official release notes for iOS 26.4.1 only mention general bug fixes. However, the update conceals a far more serious problem than the vague description suggests: iOS 26.4 introduced a bug that severely impacted iCloud synchronization on iPhones and iPads. The bug affected both Apple's own services and numerous third-party apps.
The bug was documented in Apple's developer forum and confirmed by several app developers. iPhones running iOS 26.4 no longer received iCloud change notifications—a key mechanism of the CloudKit framework that apps use to synchronize data changes between devices. As a result, changes made on one device no longer automatically synced to other iPhones and iPads.
What exactly didn't work
The error lay in CloudKit's push notification system. Normally, iCloud immediately informs all connected devices when data changes—such as a new password, an edited note, or an updated calendar entry. Under iOS 26.4, these notifications were missing, so devices were unaware that new data was available.
All apps using CloudKit were affected. On the developer forum, the creators of the popular note-taking app Drafts, among others, reported synchronization problems. But Apple's own services were also affected – especially shared passwords in the Apple Passwords app, which also rely on CloudKit.
Developers couldn't fix the problem themselves because the bug was in the operating system. All they could do was send bug reports to Apple and wait for a system update.
Which devices were affected
The bug only occurred on iOS 26.4 and iPadOS 26.4. macOS Tahoe 26.4 was not affected – iCloud synchronization worked normally on Macs throughout. Users already running the iOS 26.5 beta were also unaffected, as the bug had already been fixed there.
iOS 26.4.1: What to do now
Anyone who has noticed in recent weeks that app data is no longer reliably syncing between their iPhone and iPad should install iOS 26.4.1 immediately. The update is available via Settings > General > Software Update. After installation, the affected apps should automatically sync again the next time they connect to iCloud. The best products for you: Our Amazon storefront offers a wide selection of accessories, including those for HomeKit. (Image: Apple)
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