diff --git a/docs/en/howto/cache-control.md b/docs/en/howto/cache-control.md
index a2b4de40d..e8a6184f9 100644
--- a/docs/en/howto/cache-control.md
+++ b/docs/en/howto/cache-control.md
@@ -16,10 +16,10 @@ Default setting:
 Overriding these defaults
 
   * `[api:HTTP::$cache_age]` can be used to set the max-age component of the cache-control line, in seconds.  
-Set it to 0 to disable caching; the "no-cache" clause in `Cache-Control` and `Pragma` will be included.
+Set it to 0 to disable caching; the "no-cache" clause in `Cache-Control` and `Pragma` will be included. It works only for live sites, if `SS_ENVIRONMENT_TYPE` is set to "dev" `[api:HTTP::$cache_age]` will be always overridden with 0.
   * `[api:HTTP::register_modification_date()]` can be used to set the modification date to something more recent than the default.
 
 How it works:
 
   * `[api:DataObject::__construct()]` calls `[api:HTTP::register_modification_date()]` whenever a record comes from the database
-  * `Controller::run()` calls `[api:HTTP::add_cache_headers()]` before outputting the page
\ No newline at end of file
+  * `Controller::run()` calls `[api:HTTP::add_cache_headers()]` before outputting the page