This week one of my sub accounts was upgraded. It took me a few hours to notice that I was not getting any forwarded email to my primary account.
The reason, the Yahoo to BT Mail change wipes out any mail forwarding that existed.
Consequence, as the forwarding end on other sub accounts I will not get any notification and I need to check each sub account every few days.
It may have been to much to expect all sub accounts to change at the same time, but this is BT.🙁