Specify device family in Info.plist
check out the docs in UIDeviceFamily
if you need to only support ipad, set the DeviceFamily to 2.For iphone set to 1.For universe include both 1 and 2
As you mentioned, you should not add UIDeviceFamily in Info.plist.However, if you are generating bulid from commandline, you can set TARGETED_DEVICE_FAMILY, "1" for iPhone and "2" for iPad:
xcodebuild \ -target "${TARGET}" \ -configuration ${CONFIGURATION} \ -sdk iphoneos \ TARGETED_DEVICE_FAMILY="2"