Device in Single App Mode (KIOSK) way to push iOS 9.2.1 via MDM

We have several devices that are used in a KIOSK (Single App) mode that need to be updated to iOS 9.21 via our MDM (Mobile Iron).

Can an iOS 9.2.1 be pushed down via our MDM and it take effect on the KIOSK units?

Mobile Iron is saying its an Apple limitation currently - but I am just asking the simple question if anyone has ever done this or if this is actually a Mobile Iron issue. When we push the update its as if the unit is turned off and will not receive it.

Thanks.