This means you have to update the app compatible with iOS 11. Especially your app is a 32-bit app and you need to upgrade to 64-bit to support upcoming iOS versions.
So please open the app in the new version (take backup of the code before you start) and run the app and see what are the issues you are facing. Fix those issues and upload to the app store.
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solved Hello App need to be updated. This app need to be updadated by the developer to work on ths version of iOS