@akos @Krescht @nblucas Congratulations to all three of you!
I don’t think @JoshFossgreen ever came out and said why he went digital with the 50 first songs. I believe part of it was for people outside of the US who sign up. As some people had reported large extra charges when he would try to send the book to them. Also, since he made it digital, he was able to include extra features and replace some of the songs where he felt the difficulty was out of proportion compared to the others.
If you received a book after 21 April 2020 then he was probably just sending out any remaining copies he had.
Here is the direct link to the… 50 First Songs Pack
And here is the discussion page… 50 Songs for B2B - Upgraded and Digital 🤖
Also, I’ve added both of these links here… BassBuzz YouTube Video Guide
If you do have the book, the two resources work well together.