Apple has reportedly stopped signing iOS 18.6.2 update, preventing iPhone users who have upgraded to the recently released iOS 26 from reverting to the older software. The move follows the launch of iOS 26 just a week ago.
Apple stops signing iOS 18.6.2
When Apple “signs” an iOS version, it indicates that the software has passed the company’s server-side verification, a necessary step for installing updates on an iPhone. Without this verification, installation of the iOS version is blocked, ensuring that users cannot run outdated or potentially less secure software, reported MacRumors.
Downgrade option no longer available
While Apple is not compelling users to upgrade to iOS 26, the decision to stop signing older versions effectively removes the option to downgrade for those who have already updated. This measure aims to encourage device security and consistency across Apple devices, adds the report.
Reportedly, the restriction extends beyond iPhones. Apple has also ceased signing iPadOS 18.6.2 and tvOS 18.6, meaning that iPad and Apple TV users are similarly unable to return to previous versions after upgrading.
It is expected that users can continue on iOS 18 if they have not updated, anyone moving to iOS 26 will need to adapt to the latest features and interface changes, as reverting is no longer an option.
This is a standard practice for Apple, designed to ensure devices run the most secure and optimised software while limiting vulnerabilities associated with older versions.
iOS 26: Redesigned interface and AI integration
The iOS 26 introduces a redesigned interface and expanded use of Artificial Intelligence (AI) across supported iPhone models.
The most visible change is the introduction of ‘Liquid Glass’, a new design language applied consistently across the system. The approach gives apps, icons and controls a translucent appearance with optical qualities intended to resemble glass. Apple says the aim is to provide a sense of fluidity and uniformity across its devices.
On the Lock Screen, the time display adapts dynamically to the chosen wallpaper. Notifications shift position to ensure the central subject of a photograph remains visible, while a subtle three-dimensional effect is activated when the device is moved. The Home Screen also gains redesigned app icons with options for light and dark appearances, colour tints or a clear, see-through style.
Control Centre elements and in-app controls have been reworked to respond to their surroundings, reflecting and refracting colours and shapes while morphing fluidly to focus on content. The company describes this as a way to make the operating system feel more coherent across applications.
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