SeedCode Calendar requires FileMaker Pro 12 or higher. The calendar does not use any plugins or other trickery. This is a simple FileMaker solution like any you'd make yourself, perhaps just a little further along.
If you're using an older version of FileMaker you can download a 30 day trial of FileMaker 12 here: http://www.filemakertrial.com
You can share SeedCode Calendar with up to 9 guests without FileMaker Pro Server, providing each guest as a copy of FileMaker Pro. Even with a small number of guests, however, we strongly recommend you use FileMaker Pro Server for the best possible performance. FileMaker server also offers increased crash protection and provides for the scheduled backup of your databases, making it invaluable in our estimation.
Instant Web Publishing Requirements
Note that to publish SeedCodeCalendar via Instant Web Publishing you'll need to be using the Pro version of our calendar and will also need our Instant Web Publishing Module.
Even in our Pro version, however, support for Instant Web Publishing is very limited. If you frequently need your event information when you're out of the office consider Zulu instead of Instant Web Publishing; it is a much better experience.