I am buying Booking Calendar paid version. What do I need to do for upgrading my free or lower paid previous plugin version?

1. If you want to save previous booking data and booking settings, you need to be sure that “Delete booking data” property is checked OFF at the General Booking Settings page, otherwise all booking data will be deleted.
2. Then you need to deactivate your previous version of booking calendar. So open the WordPress Plugins menu page, then press on "Deactivate" link under the Booking Calendar. !!! IMPORTANT !!! Wait for the message, that plugin is deactivated successfully.
3. Click on Delete link of Booking plugin at Plugins menu and confirm this action.
4. Open Plugins > Add New menu page, then select “Upload” tab at the top of page. Browse the downloaded zip archive with plugin and make upload it.
5. Open WordPress Plugins menu page and click on Activate link under the Booking Calendar plugin.
!!! IMPORTANT !!! Wait for the message, that plugin is activated successfully. (The last item is important, otherwise the installation will not be complete correctly and possible some issues).
6. Configure Settings at the sub menu settings page of Booking menu an test it.