Apple released iOS 18 on Monday, along with 33 security fixes and a host of new iPhone features. Apple’s iOS 18 was released simultaneously with iOS 17.7, a security-only update for iPhone users who want to wait to upgrade their devices.

While iOS 17.7 includes 16 security fixes, iOS 18 has more than twice as many. Some of the bugs fixed in iOS 18 are serious and affect WebKit, the engine that underlies the Safari browser and the kernel of the iPhone operating system.

Among the important issues fixed in iOS 18 are two vulnerabilities in the kernel, dubbed CVE-2024-44165 and CVE-2024-44191, that could allow an app to gain unauthorized access to Bluetooth. A sandbox bug, CVE-2024-40863, could cause an app to leak sensitive information. Meanwhile, CVE-2024-40857 is an issue in WebKit where processing maliciously crafted web content could lead to universal cross-site scripting.

A second flaw in Webkit, CVE-2024-44187, could allow a malicious website to exfiltrate data across multiple origins, Apple explained on its support page.

A bug in Core Bluetooth called CVE-2024-44124 – also fixed in iOS 17.7 – could allow a malicious Bluetooth device to bypass pairing.

Some of the updates in the iOS 18 release are “quite significant” — such as the ability to connect malicious Bluetooth devices, says Sean Wright. However, many of these do not appear in version 17.7, so Wright suspects these vulnerabilities are specific to the iOS 18 beta. “My advice is that if you’re using the beta, you should update as soon as possible,” he says.

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iOS 17.7 or iOS 18?

Some people will choose to update to iOS 17.7 to wait for any initial issues with iOS 18 to be resolved. However, it’s worth noting that updating to iOS 18 will make your iPhone more secure overall.

Apple is focusing more on iPhone security fixes in iOS 18, so the range of patches is broader. In addition, a number of new security features have been added. The most significant of these is the Password app, a major improvement on iCloud Keychain that offers the same functionality as a full-fledged password manager like 1Password.

Apple’s iOS 18 also includes some cool privacy features, such as the ability to hide sensitive apps so they can only be accessed with Face ID when others are using your device.

If your iPhone can run iOS 17, it can run iOS 18. However, some of the more advanced AI features coming later this year will only be available on iPhone 15 and later.

For users considering whether to stay with iOS 17 or upgrade to iOS 18, it will be more a matter of personal preference than a security issue, Wright says. “Many people will prefer to stay with the older iOS 17 so that the initial issues in iOS 18 can be fixed – and that’s a perfectly reasonable position.”

So you know what to do. Go to Settings > General > Software Update and update to iOS 18 or iOS 17.7 now.