i just bought filemaker go for ipad.
i started the app and got the next message:

seedcode calendar: filemaker requirements
hello. this version of seedcode calendar depends upon features in filemaker 8.5 or higher and you're running go_ipad 1.1.2 I'm sorry. please visit www.seedcode.com to find calendars available for your version of filemaker pro. this solution will now quit.

what must i do to fix this?

i read that the newest calendar is quicker then my 'old' (i bought seedcode last year) and if it is possible to upgrade and it will help, then offcourse we will upgrade

can anybody give me an answer

You can certainly upgrade, but you can also simply disable the version check in the Upon Opening script in the calendar.