AutoXchange 2020 Technical Documentation

Versions of AutoCAD

DWG Versions

AutoDesk does not change the AutoCAD Drawing File Format nearly as frequently as it releases new versions, at least recently. In the early days the DWG file format was changing with pretty much every release, but while the format change for AutoCAD 2013, it did not change again until AutoCAD 2018, despite yearly releases of the program. So, the same file format was used for AutoCAD 2013, AutoCAD 2014, AutoCAD 2015, AutoCAD 2016 and AutoCAD 2017. Similarly, the format is identical for AutoCAD 2018, AutoCAD 2019 and AutoCAD 2020.

It is easy to decipher what version of AutoCAD created a given drawing file. Open the file in a text editor and look at the first six bytes (five in very early files) and match them to the following list. For DXF files this tag is given by the $ACADVER variable in the header. For instance, if the first five bytes are AC1.2 then it was created by the ancient (April 1983, so more than 35 years ago) AutoCAD Version 1.2 (or maybe AutoCAD Version 1.3, things get a little spotty back that far). If the first six bytes are AC1009 then it was created by either AutoCAD Release 11 or AutoCAD Release 12 as they shared the same format version.

If the DWG Tag value is bold in the table that means the file format changed for that version. Otherwise the file format stayed the same as in the previous version.

BTW: AutoXChange 2020 can support any version of DWG and DXF back to AutoCAD 2.5. The format changed greatly at that point and we know of no programs that support older formats. However, that was June of 1986, so the likelihood of seeing a 33+ year old AutoCAD Version 2.22 or before file is remote at best.

Name DWG tag Release Date
AutoCAD Version 1.0 MC0.0 December 1982
AutoCAD Version 1.2 AC1.2 April 1983
AutoCAD Version 1.3 August 1983
AutoCAD Version 1.4 AC1.40 October 1983
AutoCAD Version 2.0 October 1984
AutoCAD Version 2.05 AC1.50
AutoCAD Version 2.1 AC2.10 May 1985
AutoCAD Version 2.21 AC2.21
AutoCAD Version 2.22 AC2.22
AC1001
AutoCAD Version 2.5 AC1002 June 1986
AutoCAD Version 2.6 AC1002 April 1987
AutoCAD Release 9 AC1004 September 1987
AutoCAD Release 10 AC1006 October 1988
AutoCAD Release 11 AC1009 October 1990
AutoCAD Release 12 AC1009 June 1992
AutoCAD Release 13 AC1012 November 1994
AutoCAD Release 14 AC1014 February 1997
AutoCAD 2000 AC1015 March 1999
AutoCAD 2000i AC1015 July 2000
AutoCAD 2002 AC1015 June 2001
AutoCAD 2004 AC1018 March 2003
AutoCAD 2005 AC1018 March 2004
AutoCAD 2006 AC1018 March 2005
AutoCAD 2007 AC1021 March 2006
AutoCAD 2008 AC1021 March 2007
AutoCAD 2009 AC1021 March 2008
AutoCAD 2010 AC1024 March 2009
AutoCAD 2011 AC1024 March 2010
AutoCAD 2012 AC1024 March 2011
AutoCAD 2013 AC1027 March 2012
AutoCAD 2014 AC1027 March 2013
AutoCAD 2015 AC1027 March 2014
AutoCAD 2016 AC1027 March 2015
AutoCAD 2017 AC1027 March 2016
AutoCAD 2018 AC1032 March 2017
AutoCAD 2019 AC1032 March 2018
AutoCAD 2020 AC1032 March 2019
AutoCAD 2021 AC1032 March 2020
Last updated on 21 Apr 2020
Published on 21 Apr 2020