In Install Elixir, Postgres, Phoenix, and LiveView it says:
Make sure you get at least the minimal version of Elixir (>= 1.14 as of this writing), Erlang (>= 25), and Phoenix (1.7.18). The correct version of Phoenix is critical. This book will focus on that version, which has Phoenix LiveView 1.0.
And later when we are setting up authentication you have a sectionUnderstanding Phoenix 1.8’s User Scopes System which means we are not using Phoenix 1.7.18.
And some of the dependencies these days (postgrex (wants ~> elixir 1.15), swoosh (wants elixir ~> 1.16)) seem to want a higher version of elixir.