Understanding iOS Versions, Security Updates, and When to Upgrade
If you’re confused about which iOS version your iPhone should be running, you’re not alone. Apple’s approach to software updates has become increasingly complex, and it’s not always obvious whether your device is still secure or when you need to think about upgrading.
This guide explains how Apple’s iOS versioning works, what security updates mean for your device, and how to know if your iPhone is still protected.
The New Naming Convention: Why iOS Jumped to 26
If you were expecting iOS 19 after iOS 18, you might have been surprised when Apple released iOS 26 in September 2025. Apple changed their naming convention to align with the year—so iOS 26 is for 2026, similar to how car manufacturers name their models.
This actually makes things simpler going forward: if the year is 2026, you should be running iOS 26 (if your device supports it). The version number now tells you whether you’re current.
Major Updates vs Security Updates: What’s the Difference?
Apple releases two types of updates, and understanding the difference is important:
Major iOS Releases
These come once a year, typically in September, and include new features, design changes, and performance improvements. Examples include the jump from iOS 18 to iOS 26. Major releases often drop support for older devices—if your iPhone can’t run the latest major version, you won’t get new features.
Minor and Security Updates
These are released throughout the year (iOS 26.1, 26.2, etc.) and focus on bug fixes and security patches. These are the updates that protect you from newly discovered vulnerabilities. Installing these promptly is essential for security.
The Current State of iOS Support (January 2026)
Here’s where things currently stand:
iOS 26 (Current)
Supported devices: iPhone 11 and newer, iPhone SE (2nd and 3rd generation)
Status: Actively supported with regular security updates
Recommendation: If your device supports iOS 26, you should be running it
iOS 18
Supported devices: iPhone XS, XS Max, XR and newer
Status: Still receiving security updates for devices that cannot upgrade to iOS 26
Recommendation: If you have an iPhone XS/XR, stay on the latest iOS 18.x version. If your device supports iOS 26, upgrade to iOS 26
iOS 17 and Earlier
Status: iOS 17 stopped receiving updates in late 2024. iOS 16 and iOS 15 received updates in September 2025 but support is inconsistent
Recommendation: Devices stuck on iOS 17 or earlier should be considered for replacement
Which iPhones Support Which iOS Version?
Here’s a quick reference for which devices can run which iOS version:
iOS 26 (current, fully supported):
- iPhone 11, 12, 13, 14, 15, 16, 17 series
- iPhone SE (2nd generation 2020, 3rd generation 2022)
iOS 18 (security updates only):
- iPhone XS, XS Max, XR
iOS 16 (limited/no security updates):
- iPhone 8, 8 Plus, X
iOS 15 and earlier (no longer supported):
- iPhone 7 and earlier
Why This Matters for Security
Security vulnerabilities in iOS are discovered regularly. When Apple releases a security update, they also publish details of the vulnerabilities they’ve fixed. This means that once an update is released, attackers know exactly what weaknesses exist in unpatched devices.
If your device isn’t receiving security updates, known vulnerabilities remain unpatched. This is particularly concerning for devices used to access business email, banking apps, or any sensitive information.
Apple’s security updates often address vulnerabilities that are already being actively exploited—meaning attackers are using them in the real world. Running an unsupported iOS version is a genuine security risk.
What About App Compatibility?
Beyond security, older iOS versions increasingly struggle with app compatibility. App developers eventually stop supporting older iOS versions, which means apps may stop working, fail to update, or refuse to install altogether.
Banking and financial apps are often the first to drop support for older iOS versions, precisely because they take security seriously. If your banking app stops working, it’s a strong signal that your device is too old to use safely.
Business Considerations
If you use your iPhone for work—accessing company email, storing client contacts, or using business apps—security updates aren’t optional. An unsecured device connecting to business systems creates risk for your entire organisation.
Many businesses now require devices to be running a supported operating system version as part of their security policies. Mobile Device Management (MDM) systems can enforce this automatically, blocking access from devices running outdated software.
If you’re responsible for company devices, now is a good time to audit what iOS versions your fleet is running and plan replacements for any devices that can no longer be updated.
How to Check Your iOS Version
To see which iOS version you’re running, go to Settings > General > About and look for the iOS Version number.
To check for updates, go to Settings > General > Software Update. If an update is available, install it. If no update is available and you’re not running iOS 26 or the latest iOS 18.x, your device may have reached the end of its supported life.
Our Recommendations
- If your iPhone supports iOS 26: Update to iOS 26 and keep it updated
- If you have an iPhone XS/XR: Stay on the latest iOS 18.x version, but start planning for a replacement
- If you have an iPhone X or iPhone 8: Replace the device as soon as practical—these are no longer receiving reliable security updates
- If you have an iPhone 7 or earlier: Replace immediately if used for anything sensitive
Remember: your phone doesn’t stop working when it stops receiving updates. It still makes calls, sends messages, and runs apps. But it becomes increasingly vulnerable to attack, and eventually apps will stop working. The question isn’t whether your old iPhone still works—it’s whether it’s still safe.
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