Unless you're using your own projections in the DD, you should download the new one. In addition to the enhancements/fixes, the ADPs are also updated, and I find this helpful in seeing what the competition might draft.
Also, there is a problem with just getting new projections. I found (as did others) that you'll get a mess. Some players will be listed twice; once with the new projections and no ADP number, and again with the ADP number and zero as their projection. I'm in the middle of a draft and was using version d and tried to do this last night. Ugh. I'm sure glad the new version e came out this morning.
It's no big deal to download, and all your setups remain. No having to redo anything.
By the way, there are at least a couple of players whose DD projections don't match Dodds' projections. It was wrong in version d and is still wrong. Just go into the setup and fix them. It automatically saves them when you close the window by hitting OK. The players I know about are Michael Clayton and Steve McNair. There may be others, but those are the ones I came across.
Also, if you didn't know, there is a forum for all the application threads where you can read FAQs and also view previous questions and answers. If you still have questions of your own, Bruce Henderson does a nice job of keeping up with answering them.