The Nokia Lumia 920 and Lumia 820 which were initially announced to feature Bluetooth support up to version 3.1 have apparently been certified to be BT 4.0 compliant by the Bluetooth SIG yesterday. Both devices feature a B019734 Alpha engine controller subsystem designed by Nokia. What remains to be seen though is if the OS (WP8) as any kind of support for BT 4.0 in its current RTM version and if this will go to be unused until Microsoft finally adds support for it later down the road.
BT4.0 support would allow pairing and wireless communication with low power accessories like podometers and NFC like wireless syncing scenarios and payments. The Samsung ATIV S is currently listed as supporting BT 3.0 (unlike the SGSIII which is BT 4.0 so it wouldn’t surprise me if it is an OS limitation) while both the Windows Phone 8X and Windows Phone 8S by HTC only support BT2.1 + EDR.