1.18.0
The 1.18.0 release of GeoScript is build on Groovy 3.0.9, GeoTools 26.0, and the Java Topology Suite 1.18.2 and requires Java 8.
https://github.com/geoscript/geoscript-groovy/blob/master/doc/releases.rst
http://geoscript.github.io/geoscript-groovy/api/1.18.0/index.html