I've thought about it some more, I have no plans to update the course to 1.3.
The reason is that the course uses an umbrella project. The separate project (RSVP) contains the models and a lot of the logic. The web project (RSVP_Web) has the Phoenix stuff, such as controllers, templates, views, plugs, etc. It was deliberately done this way after all the talk about changes coming to Phoenix in 1.3 at last year's Elixir Conf in Orlando. Plus, thats how I've typically architected applications in other languages anyway. As a result, Phoenix's model folder was not used. Nor were controller generators (e.g. phoenix.gen.html) because I wanted to show the required parts (plus I'm not typically a fan of scaffolding anyway.)
After that, it appears the biggest change is to go from mix phoenix to mix phx but I think people can make that translation easily enough.