Migrating AutoCAD COM API applications to AutoCAD 2010
1. Change your CreateObject and GetObject calls from “AutoCAD.Application.17” to “AutoCAD.Application.18”
2. Change the reference “AutoCAD” from “AutoCAD 2009 Type Library” to “AutoCAD 2010 Type Library” (Autodesk.AutoCAD.Interop)
3. Change the reference “AXDBLib” from “AutoCAD/ObjectDBX Common 17.0 Type Library” to “AutoCAD/ObjectDBX Common 18.0 Type Library” (Autodesk.AutoCAD.Interop.Common)
See also:
http://autocad.autodesk.com/?nd=autocad_tips_tutorials_detail&adsk_tip_id=676&jid=2036
You will probably have to make some extra changes when reading/saving .dwg’s but I have yet to check those problems.