Version 0.13.1 of Geb is now available from Maven Central. The 0.13.1 version is released to address a regression discovered in the 0.13.0 release (https://github.com/geb/issues/issues/422) as well as two concurrency related issues (https://github.com/geb/issues/issues/421, https://github.com/geb/issues/issues/423).
Thanks, Marcin
