There is a new Rate Type selector for each individual rate.
The default setting means the rate takes it's booking style from the properties booking style settings as it always has.
The default setting for each rate can be over-ridden to force a specific style of booking for that particular rate, for example "ON REQUEST" or "COLLECT DEPOSIT" etc
The system will as always attempt to offer the guest the lowest price that matches their requirments and your rules.
Now if the rate used to calculate the best price has a non default Rate Type the booking will proceed with that type instead of the normal booking style.
As an example you may wish to accept 2 night or longer stays automatically but still accept 1 night stays on request.
You can do this by creating two rates, one has a 2 night minimum and is set to the default Rate Type.
The other has a 1 night minimum and is set to the On Request rate type.