Taken from the Readme file. -If you work between 2 years don't create the new year until it actually begins. You can insert reservations of the next year from the menu of the current year, extra months can be added by selecting the rates table and using the 'Add Periods' button. When the new year arrives create it and import the reservations from the previous year (to do that the same types of periods of the previous year must be used and if the periods are weekly also the same starting/ending day of the week). It is recommended to keep atcivated the option in “configure and customize” to automatically create the new year on January the 10th.
Basically just wait until the 10th of January in order for the software to create the new year automatically given that you have not unchecked the option in “configure and customize”