It’ll be interesting to see what happens to the Programming Elm book from PragProg. It’s currently in beta, and while I wouldn’t say it is useless now, certainly many of the examples will be broken.
Where are my manners - the book is for sale at https://pragprog.com/book/jfelm/programming-elm
My fears about the book being in bad shape were unfounded. PragProg don't have their usual forum up and running any more so they couldn't announce that there were updates, but seems like the author was on top of it, and released new chapters to the beta program last week. Now I can try #elm 0.19 again!