diff --git a/NEWS b/NEWS
index 4ebaca70f..2137da84f 100644
--- a/NEWS
+++ b/NEWS
@@ -1,4 +1,5 @@
 ver 0.23.16 (not yet released)
+* support libfmt 11
 
 ver 0.23.15 (2023/12/20)
 * decoder
diff --git a/src/lib/ffmpeg/LibFmt.hxx b/src/lib/ffmpeg/LibFmt.hxx
index 93bf57e6a..404515893 100644
--- a/src/lib/ffmpeg/LibFmt.hxx
+++ b/src/lib/ffmpeg/LibFmt.hxx
@@ -29,7 +29,7 @@ template<>
 struct fmt::formatter<AVSampleFormat> : formatter<string_view>
 {
 	template<typename FormatContext>
-	auto format(const AVSampleFormat format, FormatContext &ctx) {
+	auto format(const AVSampleFormat format, FormatContext &ctx) const {
 		const char *name = av_get_sample_fmt_name(format);
 		if (name == nullptr)
 			name = "?";
diff --git a/src/lib/fmt/AudioFormatFormatter.hxx b/src/lib/fmt/AudioFormatFormatter.hxx
index 6838644c4..e06e7c3d8 100644
--- a/src/lib/fmt/AudioFormatFormatter.hxx
+++ b/src/lib/fmt/AudioFormatFormatter.hxx
@@ -39,7 +39,7 @@ template<>
 struct fmt::formatter<SampleFormat> : formatter<string_view>
 {
 	template<typename FormatContext>
-	auto format(const SampleFormat format, FormatContext &ctx) {
+	auto format(const SampleFormat format, FormatContext &ctx) const {
 		return formatter<string_view>::format(sample_format_to_string(format),
 						      ctx);
 	}
@@ -49,7 +49,7 @@ template<>
 struct fmt::formatter<AudioFormat> : formatter<string_view>
 {
 	template<typename FormatContext>
-	auto format(const AudioFormat &af, FormatContext &ctx) {
+	auto format(const AudioFormat &af, FormatContext &ctx) const {
 		return formatter<string_view>::format(ToString(af).c_str(),
 						      ctx);
 	}
diff --git a/src/lib/fmt/ExceptionFormatter.hxx b/src/lib/fmt/ExceptionFormatter.hxx
index 31c9f0df2..d193689fa 100644
--- a/src/lib/fmt/ExceptionFormatter.hxx
+++ b/src/lib/fmt/ExceptionFormatter.hxx
@@ -38,7 +38,7 @@ template<>
 struct fmt::formatter<std::exception_ptr> : formatter<string_view>
 {
 	template<typename FormatContext>
-	auto format(std::exception_ptr e, FormatContext &ctx) {
+	auto format(std::exception_ptr e, FormatContext &ctx) const {
 		return formatter<string_view>::format(GetFullMessage(e), ctx);
 	}
 };
diff --git a/src/lib/fmt/PathFormatter.hxx b/src/lib/fmt/PathFormatter.hxx
index 91aca6c7c..0f4477850 100644
--- a/src/lib/fmt/PathFormatter.hxx
+++ b/src/lib/fmt/PathFormatter.hxx
@@ -29,7 +29,7 @@ template<>
 struct fmt::formatter<Path> : formatter<string_view>
 {
 	template<typename FormatContext>
-	auto format(Path path, FormatContext &ctx) {
+	auto format(Path path, FormatContext &ctx) const {
 		return formatter<string_view>::format(path.ToUTF8(), ctx);
 	}
 };