On October 13, millions of Windows PCs will stop getting security fixes unless their owners update, making this the most important “install now” season in years. Meanwhile, Apple just fixed an unprecedented 122 security flaws in iOS 27 and 204 in macOS 27, a surge experts blame on AI tools that find weaknesses faster than ever.

• Windows users, here’s what to know. Windows 11 24H2 stops getting security updates on October 13. After that date, Home and Pro PCs running 24H2 will no longer receive the monthly updates that protect against the latest threats. To check your version, go to Settings > System > About. If you see 24H2, go to Settings > Windows Update and install 25H2.

• iPhone and Mac users, you just got Apple’s biggest security update ever. iOS 27 and macOS 27 Golden Gate arrived September 14, and Apple addressed 273 unique flaws across all its operating systems in its September release. Apple also released iOS 26.7 and macOS Tahoe 26.7, so you can get the security fixes even if you’re not ready for the new look and features.

• Yes, this is worth your time. Once a flaw is fixed and made public, hackers study the fix to find devices that haven’t installed it. After October 13, every flaw discovered in Windows 11 24H2 stays unfixed, and attackers move quickly on software they know is no longer maintained. Before you update, back up your phone or computer, plug it in, and connect to Wi-Fi. On iPhone, go to Settings > General > Software Update. On Mac, go to System Settings > General > Software Update. Still on Windows 10? Microsoft extended free Extended Security Updates for home users until October 2027, but only for PCs enrolled in the program.