I assume it's safe to go ahead with DNP 2.04 directly. All releases since 2.0 were mainly bug fix release, no major changes were added.
But I guess you'ld better wait for confirmation of the DNP guys 
IBISS Internet Services & Solutions: ASP - ASP.NET 1.1/2.0/3.0/3.5 - PHP 5 - MySQL 5 - MSSQL 2005