diff --git a/src/core/include/mp-units/bits/fmt.h b/src/core/include/mp-units/bits/fmt.h
index 626a3bc83..4d1848e61 100644
--- a/src/core/include/mp-units/bits/fmt.h
+++ b/src/core/include/mp-units/bits/fmt.h
@@ -30,7 +30,7 @@
 #pragma once
 
 #include <gsl/gsl-lite.hpp>
-#include <mp-units/bits/external/hacks.h>
+#include <mp-units/compat_macros.h>
 #include <concepts>
 #include <limits>
 #include <string_view>
diff --git a/src/core/include/mp-units/customization_points.h b/src/core/include/mp-units/customization_points.h
index e085514c0..2741679e5 100644
--- a/src/core/include/mp-units/customization_points.h
+++ b/src/core/include/mp-units/customization_points.h
@@ -22,7 +22,6 @@
 
 #pragma once
 
-#include <mp-units/bits/external/hacks.h>
 #include <mp-units/bits/external/type_traits.h>
 #include <limits>
 #include <type_traits>
diff --git a/src/core/include/mp-units/math.h b/src/core/include/mp-units/math.h
index ac9ecae9e..cf5ab987d 100644
--- a/src/core/include/mp-units/math.h
+++ b/src/core/include/mp-units/math.h
@@ -22,7 +22,6 @@
 
 #pragma once
 
-#include <mp-units/bits/external/hacks.h>
 #include <mp-units/bits/value_cast.h>
 #include <mp-units/customization_points.h>
 #include <mp-units/quantity.h>
diff --git a/src/core/include/mp-units/reference.h b/src/core/include/mp-units/reference.h
index 589d9bb6f..eb0f34c5d 100644
--- a/src/core/include/mp-units/reference.h
+++ b/src/core/include/mp-units/reference.h
@@ -22,7 +22,6 @@
 
 #pragma once
 
-#include <mp-units/bits/external/hacks.h>
 #include <mp-units/bits/get_associated_quantity.h>
 #include <mp-units/bits/quantity_concepts.h>
 #include <mp-units/bits/reference_concepts.h>
diff --git a/src/systems/include/mp-units/systems/angular/math.h b/src/systems/include/mp-units/systems/angular/math.h
index 70c0fc41d..4d863a0b3 100644
--- a/src/systems/include/mp-units/systems/angular/math.h
+++ b/src/systems/include/mp-units/systems/angular/math.h
@@ -23,7 +23,6 @@
 #pragma once
 
 #ifndef MP_UNITS_IN_MODULE_INTERFACE
-#include <mp-units/bits/external/hacks.h>
 #include <mp-units/bits/value_cast.h>
 #include <mp-units/customization_points.h>
 #include <mp-units/quantity.h>
diff --git a/src/systems/include/mp-units/systems/si/math.h b/src/systems/include/mp-units/systems/si/math.h
index 777228284..053d9b368 100644
--- a/src/systems/include/mp-units/systems/si/math.h
+++ b/src/systems/include/mp-units/systems/si/math.h
@@ -23,7 +23,6 @@
 #pragma once
 
 #ifndef MP_UNITS_IN_MODULE_INTERFACE
-#include <mp-units/bits/external/hacks.h>
 #include <mp-units/bits/value_cast.h>
 #include <mp-units/customization_points.h>
 #include <mp-units/quantity.h>