Automation projects created with the AutoCAD 2014 VBA IDE, or earlier, or stand-alone applications created with Visual Basic .NET will have to be recompiled to work with the latest AutoCAD release.
AutoCAD automation projects use the type libraries
AutoCAD automation projects use the AutoCAD.Application ProgID for the CreateObject, GetObject, and GetInterfaceObject methods. For example, if you are using the CreateObject function in an AutoCAD automation project, you can use CreateObject("AutoCAD.Application") to start the most recently launched AutoCAD release on the workstation.
An automation project can start a specific release of the product, by specifying the major and/or a minor release number as part of the ProgID. For example, the ProgID