If a user installs Elixir 1.17.2 with OTP-27 as their active Erlang then beamup will install the OTP-27 version of 1.17.2. If the user then switches to using OTP-26 then there should be at least a warning printed when the user runs an Elixir command.
Another option is to offer to install the same version of Elixir but built for OTP-26 when this happens.
If a user installs Elixir 1.17.2 with OTP-27 as their active Erlang then beamup will install the OTP-27 version of 1.17.2. If the user then switches to using OTP-26 then there should be at least a warning printed when the user runs an Elixir command.
Another option is to offer to install the same version of Elixir but built for OTP-26 when this happens.