diff --git a/rebar.config b/rebar.config
index 85811854a..2e9057a3a 100644
--- a/rebar.config
+++ b/rebar.config
@@ -1,3 +1,5 @@
+{minimum_otp_vsn, "21.0"}.
+
 {deps,
     [{jsx, "2.9.0"}, % hex
      {cowboy, "2.6.1"}, % hex