diff --git a/ext/SConscript b/ext/SConscript
index 00bebae03..7d0738c2a 100644
--- a/ext/SConscript
+++ b/ext/SConscript
@@ -26,9 +26,12 @@ def prep_gtest(env):
 def prep_fmt(env):
     localenv = prep_default(env)
     license_files.append(('fmtlib', 'fmt/LICENSE.rst'))
-    build(localenv.Command("#include/cantera/ext/format.h",
+    build(localenv.Command("#include/cantera/ext/fmt/format.h",
                            "#ext/fmt/fmt/format.h",
                            Copy('$TARGET', '$SOURCE')))
+    build(localenv.Command("#include/cantera/ext/fmt/ostream.h",
+                           "#ext/fmt/fmt/ostream.h",
+                           Copy('$TARGET', '$SOURCE')))
     return localenv
 
 # each element of libs is: (subdir, (file extensions), prepfunction)
diff --git a/ext/fmt b/ext/fmt
index 404219826..e5e4fb370 160000
--- a/ext/fmt
+++ b/ext/fmt
@@ -1 +1 @@
-Subproject commit 404219826238b50c8a56e97aa5f513a97ec6b86b
+Subproject commit e5e4fb370ccf327bbdcdcd782eb3e53580e11094
diff --git a/include/cantera/base/ctexceptions.h b/include/cantera/base/ctexceptions.h
index 085b3a900..ef6ea6be1 100644
--- a/include/cantera/base/ctexceptions.h
+++ b/include/cantera/base/ctexceptions.h
@@ -11,7 +11,7 @@
 
 #include <exception>
 #include <string>
-#include "cantera/ext/format.h"
+#include "cantera/ext/fmt/format.h"
 
 namespace Cantera
 {
diff --git a/include/cantera/base/global.h b/include/cantera/base/global.h
index 207a48aac..7d12d14f0 100644
--- a/include/cantera/base/global.h
+++ b/include/cantera/base/global.h
@@ -18,7 +18,7 @@
 #define CT_GLOBAL_H
 
 #include "ct_defs.h"
-#include "cantera/ext/format.h"
+#include "cantera/ext/fmt/format.h"
 
 namespace Cantera
 {
diff --git a/include/cantera/base/stringUtils.h b/include/cantera/base/stringUtils.h
index a86324352..5df4806a8 100644
--- a/include/cantera/base/stringUtils.h
+++ b/include/cantera/base/stringUtils.h
@@ -8,7 +8,7 @@
 #define CT_STRINGUTILS_H
 
 #include "ct_defs.h"
-#include "cantera/ext/format.h"
+#include "cantera/ext/fmt/format.h"
 
 #include <string>
 
diff --git a/test_problems/surfSolverTest/surfaceSolver.cpp b/test_problems/surfSolverTest/surfaceSolver.cpp
index e1d7d516e..09906d3cd 100644
--- a/test_problems/surfSolverTest/surfaceSolver.cpp
+++ b/test_problems/surfSolverTest/surfaceSolver.cpp
@@ -18,6 +18,7 @@
 #include "cantera/kinetics.h"
 #include "cantera/kinetics/ImplicitSurfChem.h"
 #include "cantera/kinetics/solveSP.h"
+#include "cantera/ext/fmt/ostream.h"
 #include <cstdio>
 #include <fstream>
 
diff --git a/test_problems/surfSolverTest/surfaceSolver2.cpp b/test_problems/surfSolverTest/surfaceSolver2.cpp
index 0eed5e765..28f07332c 100644
--- a/test_problems/surfSolverTest/surfaceSolver2.cpp
+++ b/test_problems/surfSolverTest/surfaceSolver2.cpp
@@ -27,6 +27,7 @@ static void printUsage()
 #include "cantera/kinetics.h"
 #include "cantera/kinetics/ImplicitSurfChem.h"
 #include "cantera/kinetics/solveSP.h"
+#include "cantera/ext/fmt/ostream.h"
 #include <cstdio>
 #include <fstream>