My app is having an issue on 32-bit devices and there is a deadline to meet to release new functionality. I want to continue supporting older iOS versions and 32-bit devices, but I would like to buy myself some time to thoroughly investigate.
If I change my deployment target to iOS 11, submit and release, will Apple allow me to set it back to 10 in a future release?
The iOS Deployment Target can be any thing that you want to be.
In past I have submitted one utility app in which I was supporting from iOS 9 and above. Later I changed the deployment version to iOS 8 for supporting more customers and submitted to App Store and apple approved the same.
What Apple want is that your app's .ipa is compiled against the latest SDK.
You have to make sure that you're not calling any APIs that are available only in iOS11+. Because if you do so, you might end up with crashes for iOS10 Devices. For example, in my case, I was using CNContactPickerViewController to show contacts which is supported only from iOS 9+. So I had version check in my code for iOS 8 and used ABPeoplePickerNavigationController so as to present contact picker in iOS8 devices.
Other than this i am not seeing any potential risk that you have while downgrading the app.