RFC 4361 vs. RFC 6939

[Nicolas C.]

Hello,

To avoid conflicts of identifiers between DHCPv4 (client-identifier) and 
DHCPv6 (DUID) and make possible the use of DDNS by both clients on the 
same host, the RFC 4361 (Feb 2006) suggested to use DUID also for DHCPv4 
clients.

Now I see that the RFC 6939 (May 2013) suggests on the contrary to use 
the hardware address between DHCPv6 relay and server because the RFC 
4361 was never implemented.

I'm no sure of the implication of such a change, does it means that 
DHCPv6 relay (mostly routers?) must be modified to use this new option? 
Will it be easier (or faster) than changing the DHCPv4 clients behavior 
(which never happened)?

We have dual-stack hosts using dynamic DHCP + DNS so we experience this 
"identifiers mix" between DHCPv4 and DHCPv6. I was hoping for RFC 4361 
clients in the near future, should I have to wait for RFC 6939 routers 
instead?

Thanks,

Nicolas