The Sitefinity 4 Calendar is actually a third party add-on which is not developed by Telerik. The best approach to get assistance is to contact the publishers
of the particular add-on. I am sure they will be happy to answer all of your questions.
All the best,
the Telerik team
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items