About Custom and Third-party Application Compatibility

Changes to the AutoCAD application programming interfaces (APIs) occur with each new release, but might not require you to recompile or change existing custom programs so they work in the latest release.

With each new release, you should retest all your custom and third-party applications. Any programs that utilize commands or system variables should be reviewed to ensure the command string (such as command name, options, and values) is still valid. Also verify that no deprecated commands or system variables are being used.

The following outlines some additional changes that could affect the use of custom programs developed for an AutoCAD-based product prior to AutoCAD 2026:

Note: Starting with AutoCAD 2014-based products, custom applications must work under secure mode; when the SECURELOAD system variable is set to 1 or 2. When operating under secure mode, the product is restricted to loading and executing files that contain code from trusted locations; trusted locations are specified by the TRUSTEDPATHS system variable. For more information, see About Security and Protecting Against Viruses.