diff --git a/ext-src/swoole_http_client_coro.cc b/ext-src/swoole_http_client_coro.cc
index 8ae03ca7f2a..6aecc76546a 100644
--- a/ext-src/swoole_http_client_coro.cc
+++ b/ext-src/swoole_http_client_coro.cc
@@ -768,6 +768,33 @@ void Client::set_basic_auth(const std::string &username, const std::string &pass
     }
 }
 
+static zend_always_inline zval *sw_zend_symtable_str_add(
+    HashTable *ht, const char *str, size_t len, zend_ulong idx, bool numeric_key, zval *pData) {
+    if (numeric_key) {
+        return zend_hash_index_add(ht, idx, pData);
+    } else {
+        return zend_hash_str_add(ht, str, len, pData);
+    }
+}
+
+static zend_always_inline zval *sw_zend_symtable_str_find(
+    HashTable *ht, const char *str, size_t len, zend_ulong idx, bool numeric_key) {
+    if (numeric_key) {
+        return zend_hash_index_find(ht, idx);
+    } else {
+        return zend_hash_str_find(ht, str, len);
+    }
+}
+
+static zend_always_inline zval *sw_zend_symtable_str_update(
+    HashTable *ht, const char *str, size_t len, zend_ulong idx, bool numeric_key, zval *pData) {
+    if (numeric_key) {
+        return zend_hash_index_update(ht, idx, pData);
+    } else {
+        return zend_hash_str_update(ht, str, len, pData);
+    }
+}
+
 void Client::add_header(const char *key, size_t key_len, const char *str, size_t length) {
     zval *zheaders =
         sw_zend_read_and_convert_property_array(swoole_http_client_coro_ce, zobject, ZEND_STRL("headers"), 0);
@@ -775,12 +802,16 @@ void Client::add_header(const char *key, size_t key_len, const char *str, size_t
 
     zval zvalue_new;
     ZVAL_STRINGL(&zvalue_new, str, length);
-    zval *zresult = zend_hash_str_add(array, key, key_len, &zvalue_new);
+
+    zend_ulong idx;
+    bool numeric_key = ZEND_HANDLE_NUMERIC_STR(key, key_len, idx);
+
+    zval *zresult = sw_zend_symtable_str_add(array, key, key_len, idx, numeric_key, &zvalue_new);
     /**
      * Adding failed, indicating that this header already exists and must be converted to an array
      */
     if (!zresult) {
-        zval *zvalue_found = zend_hash_str_find(array, key, key_len);
+        zval *zvalue_found = sw_zend_symtable_str_find(array, key, key_len, idx, numeric_key);
         if (ZVAL_IS_ARRAY(zvalue_found)) {
             add_next_index_zval(zvalue_found, &zvalue_new);
         } else {
@@ -789,7 +820,7 @@ void Client::add_header(const char *key, size_t key_len, const char *str, size_t
             Z_ADDREF_P(zvalue_found);
             add_next_index_zval(&zvalue_array, zvalue_found);
             add_next_index_zval(&zvalue_array, &zvalue_new);
-            zend_hash_str_update(array, key, key_len, &zvalue_array);
+            sw_zend_symtable_str_update(array, key, key_len, idx, numeric_key, &zvalue_array);
         }
     }
 }
diff --git a/tests/swoole_http_server_coro/close_socket.phpt b/tests/swoole_http_server_coro/close_socket.phpt
index eedc0083daa..a7448f8d2f0 100644
--- a/tests/swoole_http_server_coro/close_socket.phpt
+++ b/tests/swoole_http_server_coro/close_socket.phpt
@@ -71,7 +71,7 @@ $pm->childFunc = function () use ($pm) {
                     foreach (array_merge([
                         'Content-Type' => 'application/octet-stream',
                         'X-Accel-Buffering' => 'no',
-                        'server' => 'webserver/1.0'
+                        'X-Server' => 'webserver/1.0'
                     ], $headers) as $k => $v) {
                         $socket->send("{$k}: {$v}\r\n");
                     }