In 2015, Bella is adding an extra night's headliner with support artist on the Thursday night.
You can buy a two day ticket that excludes this but allows you into the ceilidh and camping on the Thursday night as usual.
Or you can buy a three day ticket that allows you into the Garden Stage main arena on the Thursday night as well.
If you want to upgrade to a three day ticket, you need to buy a 'Weekend Ticket to Three Day Ticket upgrade'. A three day ticket allows you entry to the main stage on the thursday night for an additional night's headliner and support.