how to determine the version of an autocad DWG file

This may prove very helpful as time goes by....

To view the codes of a particular DWG file, open it within Notepad or other text editor program. The first text in the file is the code. 

MC0.0 - DWG Release 1.1 
AC1.2 - DWG Release 1.2 
AC1.4 - DWG Release 1.4 
AC1.50 - DWG Release 2.0 
AC2.10 - DWG Release 2.10 
AC1002 - DWG Release 2.5 
AC1003 - DWG Release 2.6 
AC1004 - DWG Release 9 
AC1006 - DWG Release 10 
AC1009 - DWG Release 11/12 (LT R1/R2) 
AC1012 - DWG Release 13 (LT95) 
AC1014 - DWG Release 14, 14.01 (LT97/LT98) 
AC1015 - DWG AutoCAD 2000/2000i/2002 
AC1018 - DWG AutoCAD 2004/2005/2006 
AC1021 - DWG AutoCAD 2007/2008/2009 
AC1024 - DWG AutoCAD 2010/2011/2012 
AC1027 - DWG AutoCAD 2013/2014/2015/2016/2017 
AC1032 - DWG AutoCAD 2018