There are instances that dealers need to book a vehicle for a year ahead. Before the latest update they were only able to book a service for maximum 255 days but after new Autoline update, they are able to do the bookings for more than 255 days.
Change load controls range
The first step to increase the service booking period is to increase the long range in workshop loading parameters. Navigate to Workshop loading> System Maintenance > System Parameters > Option1 tab and increase long range to maximum 400 days and hit save.
Book a service for a year ahead
Once done with changing the long range, you can book a service for a customer maximum 400 days ahead.