diff --git a/rebar.config.script b/rebar.config.script
index bbe043f..6519616 100644
--- a/rebar.config.script
+++ b/rebar.config.script
@@ -13,7 +13,7 @@ MergeConfig = fun({Key, ToAdd}, C) ->
                       end
               end.
 
-{match, [ErtsNumber]} = re:run(erlang:system_info(otp_release), "R(\\d+).+", [{capture, [1], list}]),
+{match, [ErtsNumber]} = re:run(erlang:system_info(otp_release), "(\\d+)", [{capture, [0], list}]),
 ErtsVsn = erlang:list_to_integer(ErtsNumber),
 AddErlOpts = if
                  ErtsVsn >= 15 ->