diff --git a/src/msg_handler/handler.rs b/src/msg_handler/handler.rs
index c2fe57b..34adf51 100644
--- a/src/msg_handler/handler.rs
+++ b/src/msg_handler/handler.rs
@@ -179,16 +179,16 @@ where
     let headers = response.headers_mut();
     remove_connection_header(headers);
     remove_hop_header(headers);
-    overwrite_header_entry(headers, "server", env!("CARGO_PKG_NAME"))?;
+    add_header_entry_overwrite_if_exist(headers, "server", env!("CARGO_PKG_NAME"))?;
 
     #[cfg(feature = "h3")]
     {
       if self.globals.http3 {
         if let Some(port) = self.globals.https_port {
-          overwrite_header_entry(
+          add_header_entry_overwrite_if_exist(
             headers,
             header::ALT_SVC.as_str(),
-            &format!(
+            format!(
               "h3=\":{}\"; ma={}, h3-29=\":{}\"; ma={}",
               port, H3_ALT_SVC_MAX_AGE, port, H3_ALT_SVC_MAX_AGE
             ),
@@ -270,7 +270,7 @@ where
 
     // upgrade
     if let Some(v) = upgrade {
-      req.headers_mut().insert("upgrade", v.parse()?);
+      req.headers_mut().insert(header::UPGRADE, v.parse()?);
       req
         .headers_mut()
         .insert(header::CONNECTION, HeaderValue::from_str("upgrade")?);
diff --git a/src/msg_handler/utils_headers.rs b/src/msg_handler/utils_headers.rs
index 0a8b76c..3aaebbf 100644
--- a/src/msg_handler/utils_headers.rs
+++ b/src/msg_handler/utils_headers.rs
@@ -74,17 +74,17 @@ pub(super) fn add_header_entry_if_not_exist(
   Ok(())
 }
 
-pub(super) fn overwrite_header_entry(
+pub(super) fn add_header_entry_overwrite_if_exist(
   headers: &mut HeaderMap,
-  key: &str,
-  value: &str,
+  key: impl Into<std::borrow::Cow<'static, str>>,
+  value: impl Into<std::borrow::Cow<'static, str>>,
 ) -> Result<()> {
-  match headers.entry(HeaderName::from_bytes(key.as_bytes())?) {
+  match headers.entry(HeaderName::from_bytes(key.into().as_bytes())?) {
     header::Entry::Vacant(entry) => {
-      entry.insert(value.parse::<HeaderValue>()?);
+      entry.insert(value.into().parse::<HeaderValue>()?);
     }
     header::Entry::Occupied(mut entry) => {
-      entry.insert(HeaderValue::from_bytes(value.as_bytes())?);
+      entry.insert(HeaderValue::from_bytes(value.into().as_bytes())?);
     }
   }