upgrading to fibre and odd ticket about 21CN

[#1]

Service Notice #228258759

Quote

An update report has been received for this account. The broadband service is now being transferred to the 21C Network. The transfer will complete by midnight on 14/05/2015.

I am already on 21CN, this a feature of upgrading to fibre or chinese whispers?

[#2]

This is a "feature" of Plusnet's automated mailing system. The message means "something" is happening with your account (and not what it says). In this case it (should) mean the fibre upgrade is progressing normally.
I would guess your installation date is 13/05/2015 and it will be working when the engineer leaves.

[#3]

Yup it's a automated system notification.
I've checked the order and everything looks good for the 13th.