diff --git a/lang/c++/include/avro/Node.hh b/lang/c++/include/avro/Node.hh
index f76078b..75619d9 100644
--- a/lang/c++/include/avro/Node.hh
+++ b/lang/c++/include/avro/Node.hh
@@ -219,8 +219,8 @@ inline std::ostream &operator<<(std::ostream &os, const avro::Node &n) {
 template<>
 struct fmt::formatter<avro::Name> : fmt::formatter<std::string> {
     template<typename FormatContext>
-    auto format(const avro::Name &n, FormatContext &ctx) {
-        return fmt::formatter<std::string>::format(n.fullname(), ctx);
+    auto format(const avro::Name &n, FormatContext &ctx) const {
+        return fmt::format_to(ctx.out(), "{}", n.fullname());
     }
 };
 
diff --git a/lang/c++/include/avro/Types.hh b/lang/c++/include/avro/Types.hh
index 84a3397..4fe018e 100644
--- a/lang/c++/include/avro/Types.hh
+++ b/lang/c++/include/avro/Types.hh
@@ -19,6 +19,7 @@
 #ifndef avro_Types_hh__
 #define avro_Types_hh__
 
+#include <fmt/core.h>
 #include <fmt/format.h>
 #include <iostream>
 
@@ -113,8 +114,8 @@ std::ostream &operator<<(std::ostream &os, const Null &null);
 template<>
 struct fmt::formatter<avro::Type> : fmt::formatter<std::string> {
     template<typename FormatContext>
-    auto format(avro::Type t, FormatContext &ctx) {
-        return fmt::formatter<std::string>::format(avro::toString(t), ctx);
+    auto format(avro::Type t, FormatContext &ctx) const {
+        return fmt::format_to(ctx.out(), "{}", avro::toString(const_cast<avro::Type&>(t)));
     }
 };