This release adds a comprehensive test suite, a number of small bug fixes, and updated support for newer Amber force fields including:
1. The 12-6-4 potential for treating divalent metal ions
2. The ff14ipq force field that utilizes modified off-diagonal Lennard-Jones terms.
Also added is support for NBFIX modifications in CHARMM parameter and stream files. However, the long-range correction for these systems requires OpenMM 6.1 (_not_ 6.0.1) or greater to use.
The APIs for the trajectory reporters are also significantly simplified, but this is a backwards-incompatible change.