Security firms are warning iPhone users that staying on older iOS versions is becoming risky.

Right now, adoption of iOS 26 and newer is surprisingly low — around 16% — even though Apple has started limiting some important protections to these versions only. In particular, critical WebKit zero-day fixes (the kind already being exploited in the wild) and a newer protection called Memory Integrity Enforcement are only fully available on iOS 26+.

Why this matters:
WebKit powers Safari and all in-app browsers on iOS. It’s also one of the most common ways attackers break into phones. If you’re not on iOS 26+, you may no longer be getting fixes for the most dangerous browser bugs — the ones attackers are actively using.

The new memory protections in iOS 26 also make many modern exploits much harder or outright unreliable. These aren’t small tweaks; they change how the system resists attacks at a deeper level, and they can’t really be added to older versions.

Security researchers are concerned because attackers usually go after the largest group of vulnerable users — and right now, that’s people who haven’t upgraded.

The takeaway:
If your iPhone supports iOS 26, upgrading is no longer just about new features. It’s about staying on the version Apple is clearly treating as the new security baseline. If your device can’t upgrade, it’s worth being extra cautious with links and web content — or considering a hardware upgrade sooner than you planned.