I have an old application with Document Manager that was working up to SW2014.

The application opens all files created up to SW2014 without errors. All the files created with newer versions generate an invalid license key error (as should be).

I request a new licence key for sw2017 (166 chars vs. 48 chars of 2014). Changed the key in my application.

     swDocMgr = (SwDMApplication)swClassFact.GetApplication(sLicenseKey);

creates the application without errors

     swDoc = (SwDMDocument20)swDocMgr.GetDocument(myDwg.FullName, nDocType, false, out nRetVal)

always return 0x80040112 error ("La classe non dispone della licenza per l'utilizzo" EG "The class does not have licence for use")

The Document Manager DLL version is 25.0.0.0 (SwDocumentMgr 2017 Type Library)

The application access .slddrw files created with earlier versions of Solidworks up to SW2016 (nDocType = SwDmDocumentType.swDmDocumentDrawing).

What am I doing wrong?

Thanks for your help

Best regards