This is a new release of the MBL2017 software. This release and the underlying model has been described in detail in the following paper: Keating, J.N., Sansom, R.S., Sutton, M.D., Knight, C.G., and Garwood, R.J. 2020. Morphological phylogenetics evaluated using novel evolutionary simulations. Systematic Biology. Further details of the model are available in the publication associated with the initial MBL2017 release: Sigwart, J.D., Sutton, M.D. and Bennett, K.D., 2017. How big is a genus? Towards a nomothetic systematics. Zoological Journal of the Linnean Society. The code is archived on zenodo.org. Documentation: See readme Change log: The following has been changed since the last release: Addition of character data to simulation, described in above publication. Incorporation of random numbers into software so they do not have to be loaded prior to run. Updated GUI, including addition of save path for simulation. Release information: Windows A zip containing all required binaries can be downloaded from the assets below. Alternatively an installer is provided. See notes below: Note 1: The .zip archive contains an executable MBL2017.exe. The .zip can be extracted and the program run by double clicking this.exe file in the ./bin folder. All the required libraries have been included and are found in the ./bin folder. Mac A zip containing MBL2017 can be downloaded from the assets below. To install the software, drag and drop the required .app folder(s) into the Applications folder. You may be required to the approve the software in security and privacy settings before it will launch. Linux Any Linux users willing to test a Linux build should contact palaeoware@gmail.com.