FileMaker Pro 14
FileMaker Pro is the first software requirement for using SignAgent Pro™. The most recent version that is compatible is FileMaker Pro 14.0.5.
Development is ongoing, and the next version will be completely compatible with all recent versions of FileMaker.
For more information on which versions are compatible, check out this tutorial here: FileMaker Pro Compatibility
You can learn more here: FileMaker Pro
If you need a trial version to get started, you can find that here: FileMaker Pro 14 Trial