Calendar file usage
From SpinetiX Support Wiki
The calendar files supported by SpinetiX products are based on the iCalendar file format and have ".ics" as extension.
There are many products that support the iCalendar format, like Google Calendar, Microsoft Outlook, Apple Calendar (formerly iCal), IBM Lotus Notes, Yahoo! Calendar, Mozilla Lightning Calendar extension for Thunderbird and SeaMonkey etc. See how to get data from calendar applications like these.