Forbes : Updated on Jan. 16 with new data on Apple’s iOS 26 upgrade problem.

This is not optional. Apple warns that iPhone attacks are underway and has released fixes to keep users safe. The bad news is that hundreds of millions of those users are now at risk. Check your iPhone now. And if you need to reboot, do so immediately.

Go to Settings > General > Software Update. If your iPhone is not running either iOS 26.2 or iOS 18.7.3, go to Settings > General > Shut Down and power the device off. Or you can press and hold either volume button and the side button until the power-off slider appears, » Apple says. If that doesn’t work, you can force it to restart.

Given the latest data suggests 50% of all eligible iPhone users have not yet upgraded to secure those fixes, the situation has now become urgent. Resistance to the iOS 26 upgrade has been exacerbated by Apple’s decision to make the fixes available only to iPhones or newer that have upgraded. Sticking to iOS 18 is no longer possible.