All of the tutorial videos online are based on the older version of Dorico. The new version of Dorico videos online only introduced the new features, but not “How to” videos.
You will understand that redoing all videos for each minor update will be an incredible amount of work for such a small team.
But since usually the features of Dorico mostly extent, you should find that most of the things in the older how to videos are still true in the newest version. Together with the new features video they should get you a good overview.
Anyhow, Daniel announced that they are planning to redo some of the videos with the newest version, but this will of course take some time.
There are a couple of excellent videos, both released in April last year - so, using version 4x - that take new users through the Dorico First Steps guide.
Dorico First Steps Part 1
Dorico First Steps Part 2
It’s also worthwhile browsing through Dorico’s You Tube channel to see the more recent videos