Still using my old Sky router :P

[#1]

Is this to be expected? I had confirmation that Sky broadband was being cancelled on the 26th, and Plusnet broadband being set up on the 26th, but as the Internet is still working fine, I haven't even had to plug in my new Plusnet router (which is handy as the wiring is a bit of a palaver to get to!!) 
Is it OK just to carry on with my old Sky router for now? Or is there a really good reason to swap it for the new one?
Sky also said that Sky Talk would be cancelled on the 26th, and Plusnet said the phone would be set up on the 10th Oct - phone works fine, what's really happening there!
Thanks

[#2]

Presuming the migration has been completed as it should have been (BT Wholesale's systems suggest it has), then you'd be wise to swap the router out ASAP to avoid any unnecessary downtime when Sky either cancel your account or the service is fully disconnected.
Your phone service needs to remain active to avoid any problems with the transfer to us next month.