. Warm-standby slave mode. : THis mode is still roadmap item standing IOS-XR 6.5.1
• Line card (LC) based subscribers (that is, using physical port sub-interfaces). : This feature is supported starting IOS-XR 6.5.1 ( Released Aug 2018)
• DHCP server mode. : If you looking for Local DHCP pool and Pool sync across BNG . This feature is released on IOS-XR 6.5.1 ( Released Aug 2018)
• Pseudowire Headend (PWHE), G.8032 (dual-home and ring) access technologies : Not supported yet.
Always reachable for more help :)