Is the (OS X) iTunes App Store app Information on Compatibility set from the project minimum Deployment Target, or from somewhere else?
I see one of my apps with an App store description saying "Requires iOS 6.1 or later...", but in Xcode the Deployment Target setting for the submitted build says iOS 9.3. And one of the new reviews today says that a customer tried to run it on iOS 5.1.1 (and it crashed, as the app depends on several APIs that require iOS 9 or later).
There are both Project and Target level settings in this example. Target overrides Project, so check Target settings, make needed changes and submit an update to the store. Take the current version off sale in all countries in the mean time to avoid further issues.
Best to make changes only at the Target level and leave Project level alone unless you know specifically what that change involves, etc.
If the app store says 'requires iOS6.1' then it would not be possible to load it onto a device running iOS5 unless it was jailbroken. Ask Apple to remove the review.
