AutoCAD 2013 DWG file format change
You want to know why the file format was changed in AutoCAD® 2013 and related AutoCAD vertical products and what effect this has on saving your drawings.
Since the release of AutoCAD 2010, the DWG file format has not been changed. This has allowed our customers great flexibility when implementing new versions of our software and exchanging files with clients and partners. Because of the value that this continuity provides, we seek to preserve the file format whenever possible from release to release.
However, in order to deliver customer-requested feature improvements or additions, it is occasionally necessary to update the file format. This is the case with AutoCAD 2013 and related products. We have introduced a new DWG format that has allowed us to add enhancements and functionality to a variety of features for all AutoCAD related products.
You can share your new drawings with others that are using older versions of AutoCAD products by saving the files in a format that is compatible with the previous versions of AutoCAD DWG.
Note: When saving files back to previous versions of an AutoCAD DWG format, data may be ignored and not accessible by older versions of the software, but the data should survive the "round-trip" when you reopen that older format DWG in the most recent AutoCAD version.
Autodesk is committed to working with our customers to make sure that they benefit from the exciting new features in our releases while minimizing the inconvenience a file format change may introduce.