For users of Kontact, it's possible to work in interactive mode: when you modify a contact your Memotoo address book is updated directly (and vice-versa).
Copy this address in "Remote Server URL" when you create the calendar in the application: Install the package "kdepim-kresources" to have the option "calenderar in remote file".
You must sign in or open an account to use Memotoo with iCalendar
If you choose "GroupDAV server (e.g. OpenGroupware)", enter this address in "URL":