WhatsApp is now blocking logins on devices running outdated versions of Android and iOS — not because the app itself is old, but because the underlying operating system is too vulnerable to keep using safely. The change rolled out server-side over the weekend, meaning no app update is required: users on affected devices will hit a hard stop the moment they try to verify or re-enter their account. A full-screen prompt appears, instructing them to update their OS first, with step-by-step guidance on how to check their current version and where to find system updates in Settings. Skip? Not allowed. Security is the stated reason. WhatsApp won’t say which exact OS versions are blocked. No public cutoff list, no official announcement, but GSMArena confirms the enforcement is live globally and applies to both platforms. It’s not about app compatibility. It’s about closing the door on known, unpatched exploits that attackers routinely weaponise. Especially via links or media sent through WhatsApp itself. End-to-end encryption doesn’t protect you from malware installed by clicking a poisoned link on a phone that hasn’t seen a security patch since 2019. This isn’t theoretical. Older Android versions, particularly those below Android 10, and iOS versions before iOS 15. Remain heavily targeted in the wild. WhatsApp’s move mirrors what Google and Apple have long done with their own services: tie access to minimum supported OS versions. But unlike those ecosystems, WhatsApp has no built-in OS upgrade path for older hardware. So if your Galaxy S10 is still on Android 11, or your iPhone 7 is stuck on iOS 15, you’re not just missing features, you’re being locked out. No warning. No grace period. Just a screen telling you to go update. Even if your device can’t. The rollout began quietly on 5 October 2026. It’s active now.