diff --git a/trpc/stream/http/http_stream.cc b/trpc/stream/http/http_stream.cc
index c5e15fff..61196f33 100644
--- a/trpc/stream/http/http_stream.cc
+++ b/trpc/stream/http/http_stream.cc
@@ -93,6 +93,9 @@ Status HttpWriteStream::WriteHeader() {
       if (content_length_ == kChunked) {
         response_->SetHeader(http::kHeaderTransferEncoding, http::kTransferEncodingChunked);
       }
+      if (response_->IsHeaderOnly()) {
+        content_length_ = 0;
+      }
       response_->SerializeHeaderToString(builder);
       return ContextStatusToStreamStatus(context_->SendResponse(builder.DestructiveGet()), [&] {
         state_ |= kHeaderWritten;
diff --git a/trpc/util/string/string_helper.h b/trpc/util/string/string_helper.h
index 237382f7..2157ebb1 100644
--- a/trpc/util/string/string_helper.h
+++ b/trpc/util/string/string_helper.h
@@ -33,7 +33,11 @@ inline std::optional<T> TryParse(const std::string_view& s, const Args&... args)
 /// @sa: `std::format`
 template <class... Args>
 std::string Format(const std::string_view& fmt, const Args&... args) {
+  #if FMT_VERSION >= 80000
+  return fmt::format(fmt::runtime(fmt), args...);
+  #else
   return fmt::format(fmt, args...);
+  #endif
 }
 
 /// @brief `std::string(_view)::starts_with/ends_with` is not available until C++20, so
diff --git a/trpc/util/string/string_helper_test.cc b/trpc/util/string/string_helper_test.cc
index c9cbe12d..67a6782a 100644
--- a/trpc/util/string/string_helper_test.cc
+++ b/trpc/util/string/string_helper_test.cc
@@ -271,4 +271,9 @@ TEST(String, ToLower) {
   ASSERT_EQ("abcd", ToLower("aBCd"));
 }
 
+TEST(String, FormatTest) {
+  std::string fmt_str = "this {} a {} project";
+  ASSERT_EQ(Format(fmt_str, "is", "trpc-cpp"), "this is a trpc-cpp project");
+}
+
 }  // namespace trpc::testing