If the newer file contains features unique to the latest version that did not exist in the older version, SolidWorks will prompt you to remove or modify those features before saving.
The challenge of future version files extends beyond individual users to entire teams and supply chains. Some platforms offer a sophisticated solution. They can store future-version files and allow team members with older software to access lightweight previews, Bill of Materials (BOM) data, and assembly structures without ever having to open the native file. This method provides a workaround that maintains collaboration without requiring file conversion or immediate software upgrades for everyone. solidworks future version file converter link