Apple has recently stopped signing iOS 18.6, which means if you've updated to iOS 18.6.2 or 18.6.1, there's no going back. Think of it like this: once you've crossed a bridge, you can't turn around. This move, while it might seem annoying if you preferred the older version, is actually a common practice by Apple.

Apple usually stops signing older versions of iOS shortly after a new one comes out – often within a week or two. When an update isn't signed anymore, your iPhone can't install it. This is because Apple uses a server-side software verification check. So, if you were hoping to revert to iOS 18.6 for any reason, you're out of luck.

However, there's a good reason for this. By stopping the signing of older software versions, Apple makes sure that everyone is using the latest security updates. This protects users from known vulnerabilities and potential attacks. In today's world, where cyber threats are always evolving, staying up-to-date is crucial.

For instance, iOS 18.6.1 brought back blood oxygen monitoring in the United States for the Apple Watch Series 9, Apple Watch Series 10, and Apple Watch Ultra 2 when paired with watchOS 11.6.1. Following quickly, iOS 18.6.2 provided important security fixes. These updates are essential for keeping your devices safe and functional. While it may be a pain to lose the option to downgrade, it's all part of Apple's strategy to keep its users secure.