Apple first released iOS 18 on September 16. The update introduces a host of new features to the iPhone, including customization tools, a redesigned Photos app, and major upgrades to Messages, Notes, and more.

The iOS 18 update was released at 0:00 on September 17 (Vietnam time), compatible with iPhone SE 2, iPhone SE 3 and iPhone XR and later. Four models of the iPhone 16 series will have the software pre-installed when they reach customers. This update introduces many new features for iPhone such as: customization tools, redesigned Photos app and major upgrades to Messages, Notes,....

And then Apple unexpectedly released iOS 18.0.1. According to Apple's notes, the iOS 18.0.1 update addresses issues related to the touchscreen, camera, and Messages app.

A week later, Apple stopped signing iOS 18. This move did not come as much of a surprise to iOS users as Apple regularly stops signing older versions of iOS to prevent users from downgrading. When an update is stopped signing, it cannot be installed on the iPhone due to server-side software verification checks.

Thus, after users update to the latest iOS 18.0.1, they will no longer be able to downgrade to previous iOS versions.

Currently, iOS 18.0.1 is the latest official iOS version. Besides, the company is still testing iOS 18.1 for official release next month.