diff --git a/src/core/include/mp-units/bits/core_gmf.h b/src/core/include/mp-units/bits/core_gmf.h
index 65210a7c..e37d8d8f 100644
--- a/src/core/include/mp-units/bits/core_gmf.h
+++ b/src/core/include/mp-units/bits/core_gmf.h
@@ -22,7 +22,6 @@
 
 #pragma once
 
-// core
 #include <gsl/gsl-lite.hpp>
 #include <mp-units/bits/external/hacks.h>
 #include <mp-units/compat_macros.h>
@@ -41,11 +40,12 @@
 #include <optional>
 #include <random>
 #include <ranges>
-#include <string>
+#include <sstream>
 #include <string_view>
 #include <tuple>
 #include <type_traits>
 #include <utility>
 
-// si
-#include <chrono>
+#if __cpp_lib_text_encoding
+#include <text_encoding>
+#endif
diff --git a/src/systems/mp-units-systems.cpp b/src/systems/mp-units-systems.cpp
index d5158982..81d2732c 100644
--- a/src/systems/mp-units-systems.cpp
+++ b/src/systems/mp-units-systems.cpp
@@ -1,7 +1,7 @@
 module;
 
 #include <mp-units/bits/core_gmf.h>
-#include <mp-units/compat_macros.h>
+#include <chrono>
 
 export module mp_units.systems;