To make discounts more flexible the dates in which a discount are valid are now set day by day rather than for a date range. Previously there was a Booking date range and an Arrival date range. This has been replaced by a grid that covers every day of the year. For a discount to be valid it has to be used on an item or reservation that is both booked on a valid date and arrives on a valid date. If either date is not valid the discount is not applicable. These date ranges apply to online as well as office reservations. Previously, discounts without dates applied in the office were valid, that is no longer the case. All discounts must now pass the booking and arrival date test.
If you had date ranges previously they will be converted to the daily format. If the date ranges were left blank then they will be converted to 1/1/2015 and 12/31/2015 so that the discounts will work this year. You will need to update the dates for 2016 and beyond.
The advantage to the new way is increased flexibility as to when the discounts are valid. For example you can have a broad range of booking dates but only for reservations arriving on weekdays, or Tuesdays, or Sundays, etc. And vice-verse, reservations booked on certain days but arriving on any day could qualify for a discount.