The 3CX iOS app supports iOS 15 and above
To ensure reliable performance and support the most advanced technologies, the 3CX iOS app will only work on iOS 15 and above for the near future. This limitation will take effect with the release of the upcoming 3CX iOS V18 Update 8. We recommend that you update the iOS app as soon as possible.
Supported iOS device versions
iPhone 6S, iPhone SE and later
iPad Air 2, iPad Air 3rd generation and later
3CX apps for iOS installed on devices with previous versions of iOS will no longer receive updates - i.e. new features and various fixes.
You can provide feedback on the 3CX App for iOS 15 and above on the 3CX forum.