I highly recommend using the hexpm docker images, which you specify with elixir, erlang, and distro versions, e.g. hexpm/elixir1.12-erlang24.0-debian-buster.
Since the official Elixir versions aren't pinned to a version of Erlang, we had issues where either Erlang or the distro should change out from under us. But not with the hexpm ones.
Since the official Elixir versions aren't pinned to a version of Erlang, we had issues where either Erlang or the distro should change out from under us. But not with the hexpm ones.