If you need to exchange files across SOLIDWORKS versions today, here is the (no third-party purchase required):
If your model contains new features or geometry types unique to the newer version, SolidWorks cannot translate them backward. solidworks future version file converter link
Uploading proprietary 3D CAD models to a free online converter exposes your company's intellectual property to unsecured servers. If you need to exchange files across SOLIDWORKS
: If your design uses features that do not exist in the older version, the software will notify you to address these incompatibilities before saving. Consecutive Release Interoperability (SP5) solidworks future version file converter link