The most recent edition of the Digital Tradition readily available is from 2002. There were some later editions, but they had technical troubles. So, this is the best we have:

https://mudcat.org/download/DTSpring2002MSDOS.zip

Somebody emailed me to ask how to download the DT tunes so he could convert them into another format. There's a separate file in the DT download called TUNE.ZIP. That ZIP file contains all the DT tunes, in SongWright format. I have checked a lot of these tunes for accuracy, and have almost always found them to be accurate. Dick Greenhaus did an exceptionally good job of transcribing these tunes.
-Joe-