This was a post 40 minutes ago on the VM forums.
Q) My gran has a old virgin tv box and out of no where all her channels have disappeared, she is paying her monthly bills ect, iv tried following the instructions on line but they are for the newer boxes
A) All of the oldest V boxes were decommissioned on the 1st July.
This hasn't been out of nowhere, for the last couple of years Virgin Media have been contacting customers with these boxes at different times to offer a swap to their a TiVo or V6 box.
There have also been many on screen messages advising the boxes will stop working.
You will now need to contact Virgin Media to get a new box arranged for delivery or installation.
So it is certainly happening just a case of when.