You can watch on my yt chan here:
https://www.youtube.com/playlist?list=PL0lNJEnwfVVNQIpSNDeJr...
221 karma · joined November 10, 2016
So to keep all of them at the same major version, they pushed everything to version 4.
Also, the jump from AngularJS (1) to Angular 2 was drastically different. Going from 2 to 4 however is much less significant in terms of breaking changes.
You won't have to relearn hardly anything if you already know 2.
Install the latest version of the CLI: npm install -g @angular/cli
And then run: ng new project-name --ng4
The "--ng4" flag is currently required, as it doesn't yet install ng4 by default.