The TomTom/Webfleet PRO 8275 device uses the Android 4.3 (Jelly Bean) Operating System, updateable to Android 6. AllOnMobile v3.1.x is the last release of AllOnMobile/ Whitespace Mobile that will support the Android 4.3 Operating System.
The Webfleet PRO 8375 device uses the Android 6 Operating System, not updateable. Availability of these devices ended in Spring 2021.
The Webfleet PRO 8475 device (from 2021) uses the Android 9 Operating System.