Please note that the current implementation of Aspose.Imaging API does not support the DWG 2007 (AC1021) format. Feature request ticket has been created with ID IMAGING-35129.
Note that we have just logged the ticket so we will require some time to analyze the feasibility of your request in order to bring it on our road map of Aspose.Imaging API. As soon as we have completed the preliminary analysis, we will post here with estimated release schedule.