IsRebar3 = case application:get_key(rebar, vsn) of
               {ok, Vsn} ->
                   [MajorVersion|_] = string:tokens(Vsn, "."),
                   (list_to_integer(MajorVersion) >= 3);
               undefined ->
                   false
           end,

Rebar2Deps = [
              {cf, ".*", {git, "https://github.com/project-fifo/cf", {tag, "0.2.2"}}}
             ],

case IsRebar3 of
    true -> CONFIG;
    false ->
        lists:keyreplace(deps, 1, CONFIG, {deps, Rebar2Deps})
end.