diff --git a/conf/nginx.conf b/conf/nginx.conf
index 9b35a60..c9f262c 100644
--- a/conf/nginx.conf
+++ b/conf/nginx.conf
@@ -26,7 +26,7 @@ location __PATH__/ {
   location ~* ^[^(\.php)]+\.(jpg|jpeg|gif|png|ico|css|pdf|ppt|txt|bmp|rtf|js)$ {
     access_log off;
     expires 1h;
-    add_header Cache-Control public;
+    more_set_headers "Cache-Control: public";
   }
 
   # Include SSOWAT user panel.