Full feature API for setting up, running, and analyzing experiments Supports new generalized MCMC moves, ThermodynamicStates, and other features from improved OpenMMTools Checkpoint feature added to reduce file size, add portability to data analysis files. Simulations can now alternate between phases to allow analysis even before simulations are done OpenEye features compartmentalized so you don't need every OpenEye feature YANK could use to use any of them Major under the hood speed ups to base code and MPI behavior, includes a full code refactor. Mol2 files can now read in multi-molecule files No longer uses standalone Alchemy module, uses the one built into OpenMMTools Added Python 3.6 support. Retired Python 3.4 support