About the app compatibility alert on iPhone, iPad, or iPod touch

If you see an alert that says an app isn’t compatible with the iOS version on your device, learn what to do.

When using a third-party app, you might see one of these alerts:
[app name] needs to be updated. This app will not work with future versions of iOS. The developer of this app needs to update it to improve its compatibility.
[app name] needs to be updated. The developer of this app needs to update it to work with iOS 11.

These alerts mean that an app needs to be updated by the developer to support iOS 11. To view a list of apps on your device that need to be updated, go to Settings > General > About > Applications.
If you have an app that needs to be updated, try the following:
Check the App Store for an updated version of the app. Depending on the app developer, you might need to download a different app, or purchase an upgrade to a later version of the app.
Contact the developer or check their website for more information.

If a developer no longer supports or develops the app, you can search the App Store for similar apps created by other developers.

Source: support.apple.com