diff --git a/src/xmessage.cpp b/src/xmessage.cpp
index 1ab9544..5a14ba0 100644
--- a/src/xmessage.cpp
+++ b/src/xmessage.cpp
@@ -13,6 +13,7 @@
 #include <sstream>
 #include <string>
 #include <utility>
+#include <ciso646>
 
 #include "nlohmann/json.hpp"