JTS 1.19 has just been released! There is a great deal of new, improved and fixed functionality in this release - see the GitHub release page or the Version History for full details.
This blog has several posts describing new functionality in JTS 1.19:
New Functionality
- Concave Hull of Polygons
- Algorithm for Concave Hull of Polygons
- Outer and Inner Concave Polygon Hulls
- Using Outer Hulls for Smoothing Vectorized Polygons
- Concave Hulls
- Polygon Triangulation
- Cubic Bezier Curves
- Offset Curves
Improvements
Many of these improvements have been ported to GEOS, and will appear in the soon-to-appear version 3.11. In turn this has provided the basis for new and enhanced functions in the next PostGIS release, and will likely be available in other platforms via the many GEOS bindings and applications.