diff --git a/Plugins/Prism/Filters/vtkPrismGeometryConverter.cxx b/Plugins/Prism/Filters/vtkPrismGeometryConverter.cxx
index 0ba008c239..686adeae19 100644
--- a/Plugins/Prism/Filters/vtkPrismGeometryConverter.cxx
+++ b/Plugins/Prism/Filters/vtkPrismGeometryConverter.cxx
@@ -9,7 +9,7 @@
 
 // clang-format off
 #include <vtk_fmt.h> // needed for `fmt`
-#include VTK_FMT(fmt/core.h)
+#include VTK_FMT(fmt/format.h)
 // clang-format on
 
 //------------------------------------------------------------------------------
diff --git a/VTKExtensions/Core/vtkPVDataUtilities.cxx b/VTKExtensions/Core/vtkPVDataUtilities.cxx
index 21fbca502b..8fb7c148ad 100644
--- a/VTKExtensions/Core/vtkPVDataUtilities.cxx
+++ b/VTKExtensions/Core/vtkPVDataUtilities.cxx
@@ -15,7 +15,7 @@
 
 // clang-format off
 #include <vtk_fmt.h> // needed for `fmt`
-#include VTK_FMT(fmt/core.h)
+#include VTK_FMT(fmt/format.h)
 // clang-format on
 
 namespace
diff --git a/VTKExtensions/Core/vtkPVStringFormatter.h b/VTKExtensions/Core/vtkPVStringFormatter.h
index 771052ecad..27be619a42 100644
--- a/VTKExtensions/Core/vtkPVStringFormatter.h
+++ b/VTKExtensions/Core/vtkPVStringFormatter.h
@@ -26,7 +26,7 @@
 #include <vtk_fmt.h> // needed for `fmt`
 #include VTK_FMT(fmt/args.h)
 #include VTK_FMT(fmt/chrono.h)
-#include VTK_FMT(fmt/core.h)
+#include VTK_FMT(fmt/format.h)
 #include VTK_FMT(fmt/ranges.h)
 // clang-format on
 
@@ -357,7 +357,7 @@ private:
      * If argument already exists, it's ignored.
      */
     template <typename T>
-    void AddArg(const fmt::detail::named_arg<char_type, T>& fmtArg)
+    void AddArg(const fmt::named_arg<T, char_type>& fmtArg)
     {
       bool argNotFound = std::find_if(this->Arguments.begin(), this->Arguments.end(),
                            [&fmtArg](const vtkNamedArgument& arg) {
diff --git a/VTKExtensions/IOCore/vtkParallelSerialWriter.cxx b/VTKExtensions/IOCore/vtkParallelSerialWriter.cxx
index 5f1833ba29..23c4a9d7c9 100644
--- a/VTKExtensions/IOCore/vtkParallelSerialWriter.cxx
+++ b/VTKExtensions/IOCore/vtkParallelSerialWriter.cxx
@@ -29,7 +29,7 @@
 
 // clang-format off
 #include <vtk_fmt.h> // needed for `fmt`
-#include VTK_FMT(fmt/core.h)
+#include VTK_FMT(fmt/format.h)
 // clang-format on
 
 namespace