You can save a drawing in a format compatible with previous versions of the product.
You can save a drawing created with the current release of the program in a format compatible with previous versions. This process creates a drawing with information specific to the current release stripped out or converted to another object type.
If you use the current release to open a drawing created with a previous release, and you do not add any information specific to the current release, you can then save the drawing in the format of the previous release without loss of data.
If you need to keep a drawing created in a previous release in its original format, either mark the file as read-only, or open it in the current release and use the File Type options in the Save As dialog box to save it in its original format.
Because saving a drawing in an earlier release format may cause some data loss, be sure to assign a different name to avoid overwriting the current drawing. If you overwrite the current drawing, you can restore the overwritten version from the backup file (filename.bak) that is created during the saving process.
Associative dimensions created in AutoCAD 2002 or later generally maintain their associativity when saved to a previous release and then reopened in the current release. However, if you modify dimensioned objects using a previous release to the extent that new objects are formed, the dimension associations change when the drawing is loaded into the current release. For example, if a line that was dimensioned is trimmed so that an interior portion of the line is removed, two line objects result and the associated dimension applies to only one of the line objects.
Dimension associativity is not maintained when a drawing is saved as an AutoCAD R12/LT 2 DXF file and then reopened in the current release.
Drawings saved to a legacy drawing file format (AutoCAD 2007 or AutoCAD LT 2007 or earlier) do not support objects greater than 256MB.
Saving a drawing containing model documentation drawing views in Release 2012 format has the following limitation:
Saving a drawing in Release 2000/LT 2000 format is subject to the following limitations:
Saving a drawing in Release 14/LT 98/LT 97 format is subject to the following limitations:
Saving a drawing in Release 12/LT 2 DXF format is subject to the following limitations: