AutoLISP programs commonly require very few changes in order to run on the latest release.
However, an AutoLISP program might no longer run correctly on the latest release because an AutoLISP function, or AutoCAD-based product command has been changed or deprecated.
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 AutoCAD-based 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 Protecting Against Malicious Code.