diff --git a/src/ejabberd_redis.erl b/src/ejabberd_redis.erl
index 05fa5e497..46fe8ce90 100644
--- a/src/ejabberd_redis.erl
+++ b/src/ejabberd_redis.erl
@@ -69,6 +69,14 @@
 
 -export_type([error_reason/0]).
 
+-ifdef(USE_OLD_HTTP_URI). % Erlang/OTP lower than 21
+-dialyzer([{no_return, do_connect/6},
+           {no_unused, flush_queue/1},
+           {no_match, flush_queue/1},
+           {no_unused, re_subscribe/2},
+           {no_match, handle_info/2}]).
+-endif.
+
 %%%===================================================================
 %%% API
 %%%===================================================================