diff --git a/src/cowboy_middleware.erl b/src/cowboy_middleware.erl
index 0c1ca770..3d58627d 100644
--- a/src/cowboy_middleware.erl
+++ b/src/cowboy_middleware.erl
@@ -30,7 +30,7 @@
 
 -callback execute(Req, Env)
 	-> {ok, Req, Env}
-	| {suspend, module(), atom(), any()}
+	| {suspend, module(), atom(), [any()]}
 	| {halt, Req}
 	| {error, cowboy_http:status(), Req}
 	when Req::cowboy_req:req(), Env::env().
diff --git a/src/cowboy_sub_protocol.erl b/src/cowboy_sub_protocol.erl
index 0b231d3d..babc6f2d 100644
--- a/src/cowboy_sub_protocol.erl
+++ b/src/cowboy_sub_protocol.erl
@@ -31,7 +31,7 @@
 
 -callback upgrade(Req, Env, module(), any())
 	-> {ok, Req, Env}
-	| {suspend, module(), atom(), any()}
+	| {suspend, module(), atom(), [any()]}
 	| {halt, Req}
 	| {error, cowboy_http:status(), Req}
 	when Req::cowboy_req:req(), Env::cowboy_middleware:env().