diff --git a/sim/kelvin_state.cc b/sim/kelvin_state.cc
index 2b1dbbc..c1d4c8b 100644
--- a/sim/kelvin_state.cc
+++ b/sim/kelvin_state.cc
@@ -1,6 +1,7 @@
 
 #include "sim/kelvin_state.h"
 
+#include <any>
 #include <cstdint>
 #include <iostream>
 #include <ostream>