Starting 1.21 the settings related to booking can be found in Theme Options-General-Booking Settings:
Select Weekend days
You can select the weekdays to be Sunday and Saturday, Friday and Saturday, Friday, Saturday and Sunday.
Select Date Format for datepickers
Includes date formats yy-dd-mm (default), yy-mm-dd, mm-dd-yy, dd-mm-yy, dd-yy-mm, mm-yy-dd
Maximum Guest number
You can set the maximum guest number.
Maximum Month number
The number of months that will show in the calendar can be set here.
The calendar from booking form will not be affected by this option, the month number there is unlimited. If you wish set the same number of months here as well please check this help