--- a/xml/en/docs/http/ngx_http_headers_module.xml
+++ b/xml/en/docs/http/ngx_http_headers_module.xml
@@ -10,7 +10,7 @@
 <module name="Module ngx_http_headers_module"
         link="/en/docs/http/ngx_http_headers_module.html"
         lang="en"
-        rev="4">
+        rev="5">
 
 <section id="summary">
 
@@ -56,6 +56,14 @@ the response code equals 200, 201, 204, 
 A value can contain variables.
 </para>
 
+<para>
+There could be several <literal>add_header</literal> directives.
+These directives are inherited from the previous level if and
+only if there are no
+<literal>add_header</literal>
+directives defined on the current level.
+</para>
+
 </directive>