What is an Operating System?

An operating system (OS) is the core software that runs a phone, tablet, or computer.

This page explains which operating systems are supported for accessing work-related applications (such as Microsoft 365) on personal devices.

Key only supports operating systems that are still actively supported by their manufacturer and continue to receive security updates.

Staff must keep devices and apps up to date to protect organisational and personal data.

Apple

• iPhone iOS: Versions 16, 18, and 26 supported.
• iPadOS: Versions 16, 17, 18, and 26 supported.
• macOS: Versions 14 (Sonoma), 15 (Sequoia), and 26 (Tahoe) supported.
• Important: iOS 17 is no longer supported.  However, any device running iOS 17 can be upgraded to iOS 18.

Google

• Android: Versions 14, 15, 16, and 17 supported.
• ChromeOS: Version 145 and later supported.
• Important: Android 13 reached end of support in January 2026 and no longer receives security updates.  Android updates may be dependent on the device manufacturer.  Check your manufacturers website for information about updates.

Microsoft Windows

• Windows 11: Versions 24H2, 25H2, and 26H1 supported.
• Important: Windows 10 reached end of general support in October 2025.

How to Check Your Version

Here are instructions for checking the OS version on:

• iPhone/iPad: Settings → General → Software Update.
• Mac: System Settings → General → Software Update.
• Android: Settings → About Phone → Software Information.
• ChromeOS: Settings → About ChromeOS.
• Windows: Start → Settings → System → About.