Which Cisco IOS XR version or versions support the BNG functionality?

classical Cisco IOS XR only

Cisco IOS XR $64-$bit v$6\mathrm{.}1\mathrm{.}1$ and later

both Cisco IOS XR $32-$bit and IOS XR $64-$bit $!!!!!!!!!!!!!!!!!!!$

only Cisco IOS XR $32-$bit v$4\mathrm{.}3\mathrm{.}0$ and later