Will deregistering a BT4600 handset, in order to register it to a brand new BT4600 base unit, wipe the contacts? Is there any way I can retain the contacts if so?
I don't think there's a way to export and import contacts between the old and new base unit
See: https://community.bt.com/t5/Home-phone-including-Digital/Changing-BT4600-base-station/td-p/2267332