case os:getenv("TARGET_ERLANG_VERSION") of
    false -> CONFIG;
    [] -> CONFIG;
    TargetErlangVersionString ->
        GpbOpts = proplists:get_value(gpb_opts, CONFIG),
        TargetErlangVersion = {target_erlang_version, list_to_integer(TargetErlangVersionString)},
        NewGpbOpts = lists:keystore(target_erlang_version, 1, GpbOpts, TargetErlangVersion),
        lists:keystore(gpb_opts, 1, CONFIG, {gpb_opts, NewGpbOpts})
end.