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vCalendar VCS/ICS Considerations

A vCalendar (VCS/ICS) file is a text file containing calendar information. It is supported as an input source by Microsoft Outlook, and as both input and output by several other calendar systems.

Many IMAP or POP3 based email systems import or export calendars in the ICS or VCS format, so choose this format if you need to transfer data between systems, and if it supports this format.


  • No additional software is required.
  • The vCalendar data file has the VCS or ICS file extension, but it can have any extension. Kerio stores vCalendar files with the .EML file extension.