Something that I have been concerned about, regarding digital service, is what happens if you have a power cut? Digital service means your telephone will need to be plugged into your router. So it looks like BT have been proactive about this and has started sending out power banks to customers. This was my first one this morning for and elderly couple. Essentially it's a 'UPS' (uninterruptible power supply) that will remain powered on in the event of a power cut and your router and 'ONT' (optical network terminal) will remain on.
Digital Service Update
Updated: Feb 10