This is a patch release containing the following fixes.
#4410: Write DCD version as 24 instead of 21 to fix ability of CHARMM to read DCD trajectories written by OpenMM.
#4461: Fixed memory leak
#4485: Avoid overflow in large XTC files
#4508: Fixed error when using both CustomNonbondedForce and LennardJonesForce
#4531: Allow multiple registrations of the same atom type if definitions identical.