I agree with the above posts.
Depending on the CAD system, you may have to archive the old format files and recreate them for new or updated parts.
The important thing is to understand how the different versions of the standard will affect the interpretation of the part requirements, and how that affects anyone that has to rely on that data. That said, it is probably not a good idea to update existing drawings.
"Good to know you got shoes to wear when you find the floor." - [small]Robert Hunter[/small]