diff --git a/oxenmq/oxenmq.h b/oxenmq/oxenmq.h
index e2e9b83..17ce052 100644
--- a/oxenmq/oxenmq.h
+++ b/oxenmq/oxenmq.h
@@ -44,6 +44,7 @@
 #include <atomic>
 #include <cassert>
 #include <cstdint>
+#include <future>
 #include "zmq.hpp"
 #include "address.h"
 #include "bt_serialize.h"
@@ -56,10 +57,6 @@
 #error "ZMQ >= 4.3.0 required"
 #endif
 
-namespace std {
-template <class R> class promise;
-}
-
 namespace oxenmq {
 
 using namespace std::literals;