x_t (parasolid) files as a neutral 3rd party file. So what can you do if you need to send the file to someone using 2 or 3 year older version of SOLIDWORKS? The best route is to send a parasolid. See this help article for it's capabilities. This is only available in the sp5 version of each year and it has limited functionality. That means you can open a 2020 part or assembly in 2019sp5 or a 2021 file in 2020sp5. In 2014 sp5 SOLIDWORKS introduced a way to open parts and assemblies in a read-only state 1 version previous to the version it was saved in. SOLIDWORKS is backward compatible, (meaning you can open a 2017 file in SOLIDWORKS 2018) but is limited in forward compatibility (opening a 2018 file in 2017). With each new year version of SOLIDWORKS, the chance that you will need to send a file to a user or customer that uses a previous year's version grows.
