In order to upgrade V6 box software to 360, you will need to have got a new remote control from Virgin as pictured.
360 Remote
I've read elsewhere on the forum that once this remote is paired the update becomes available in the apps section of the V6 software, however eventually all boxes will get the update, if you've not been sent the new remote I would have a look through the TV 360 section of this forum before deciding if you want it yet as there are some issues and a lot of missing features compared to V6