Hello OpenSim Testers, We are excited to announce the beta release of OpenSim 4.1 and we would love to have your help in testing the new software! We would appreciate getting input by January 21. The OpenSim 4.1 beta has many improvements and bug fixes that we are excited to get into your hands. We are especially excited about this release because OpenSim 4.1 debuts methods to use IMU data for inverse kinematics. A more detailed list of what’s new in OpenSim can be found here <https://simtk-confluence.stanford.edu/pages/viewpage.action?pageId=36439186> . We are looking for testers, whether you have time to test one thing or ten. To get started, install the OpenSim 4.1 Beta <https://simtk.org/frs/?group_id=91> (scroll down to "OpenSim Beta Releases") and visit the shared testing doc <https://docs.google.com/spreadsheets/d/1U8yoMh6CFIF-sXfDVW6pdOgftlFmhRp3kY1gPj3uvqc/edit?usp=sharing> for instructions and a list of tasks to test. You can test out the bug fixes, try out the new IMU features, or run through an example or two. It would also be very helpful to test the new IMU features with your own data. Please don't hesitate to send any questions or feedback via email as well. Thanks in advance for your help and happy new year! - The OpenSim Team -- *Jennifer Hicks, Ph.D.* Director of Data Science | Mobilize Center <http://mobilize.stanford.edu> Associate Director | NCSRR <http://www.stanford.edu/group/opensim/about/index.html> R&D Manager | OpenSim <http://opensim.stanford.edu/> Stanford University 650-498-4403 | jenhicks@stanford.edu