As of Elixir 0.13, you’ll need to have Erlang 17 installed. If you use brew to install erlang then elixir you’ll find this message awaiting you:
ERROR: OTP release R16B03-1 does not match required regex (17).*
The current Erlang brew formula is still at R16B03-1. BUT! the development version IS 17. So here you go:
brew install --devel erlang
I’m sure this will change soon, but until then this’ll get you going again.