How to best sync with apple calendar?

Hi everyone,

I just bought a premium package of Weekplan because I really like the concept behind it. Now I have the question: How do I get all my personal appointments from my iPhone / Mac calendar (standard Apple calendar) into Weekplan. I know this is not a Weekplan feature yet so I need a smooth, free and easy workaround. I don't need a two-way sync, just to pull in all events into Weekplan and react to changes I make in my calendar (like moving an appointment or deleting an instance of a recurring event because it falls on a holiday). My favourite integration tool Zapier doesn't work with Apple Calendar. IFTTT seems to do work with iCal but it doesn't integrate with Weekplan.

Any ideas are greatly appreciated.