Piplin has a mailing list. Feel free to join it and ask any questions you may have.
To subscribe for announcements of releases, important changes and so on, please follow @dgrnbrg on Twitter.
If you find a bug, poor default, missing feature or find any part of the API inconvenient, please file an issue on Github. If possible, try to explain what behavior you expected and why. Bonus points for contributing failing test cases.
Piplin uses Leiningen 2. Make sure you have it installed and then run tests against supported Clojure versions using
lein testThen create a branch and make your changes on it. Once you are done with your changes and all tests pass, submit a pull request on Github.