Updated 9:40 am, Oct 16. If you are a Studio Manager user, don’t forget to check that your version of FileMaker Pro is compatible before you upgrade to OS X Yosemite or any other version of OS X above your current version. Here is the URL from filemaker.com.
As of 9 am, OS X Yosemite is not listed as to whether any versions of Yosemite are compatible. I hope to see Yosemite added to this list within 24 hours of the official Yosemite release. So check this page before upgrading.
For what it is worth MIT Information & Technology Knowledge base says the OSX Yosemite Gold Master 3 was OK for FileMaker Pro 13 but not for FileMaker Server 13 when I looked at it today.