Presently i am working on ACAD2011 but some of our customers have older version Acad, hence we save the drawings in ACAD2000 format and send it. I would like to know what is the major differance/ property change when we save it to older version. Also would like to know the differance of property when we save in ACAD2000 and ACAD2004. I feel ACAD2011 version drawings saved in ACAD2000 will loose some properties and also we may loose some properties if saved in ACAD2004. Can anybody help me informing the main differances of ACAD2000 and ACAD2004 drawing properties?