1.15.0
The 1.15.0 release of GeoScript is build on Groovy 3.0.1, GeoTools 23.0, and the Java Topology Suite 1.16.1 and requires Java 8.
https://github.com/geoscript/geoscript-groovy/blob/master/doc/releases.rst
http://geoscript.github.io/geoscript-groovy/api/1.15.0/index.html