The 3.8 code for Fabrik is now available on github, in the 'master' branch. If you are familiar with updating Fabrik from github, we would appreciate it if you could test this code on J! 3.8 for us. Once we have some feedback, we'll build a 3.8 release.
The pages linked to from here describe: 1) the licenses for copying, modifying or redistributing Fabrik; and 2) for contributing code to the Fabrik project.