There is a two part answer here:
1. Windows RT: only USB Sticks that support the new NDIS 6.3 interface from Microsoft will work on Windows RT. The first Vodafone USB Sticks with NDIS 6.3 will be the K4305 and K4305-Z. Also, Windows RT tablets can be used with our Mobile Wi-Fi products (using a Wi-Fi connection).
2. Windows 8 and Windows 8 Pro: please check our compatibility list on http://support.vodafone.com/windows8