--- a/xml/en/docs/http/ngx_http_limit_req_module.xml	Wed Aug 29 21:48:00 2018 +0300
+++ b/xml/en/docs/http/ngx_http_limit_req_module.xml	Thu Aug 30 22:53:18 2018 +0300
@@ -10,7 +10,7 @@
 <module name="Module ngx_http_limit_req_module"
         link="/en/docs/http/ngx_http_limit_req_module.html"
         lang="en"
-        rev="8">
+        rev="9">
 
 <section id="summary">
 
@@ -163,7 +163,8 @@
 <syntax>
     <value>key</value>
     <literal>zone</literal>=<value>name</value>:<value>size</value>
-    <literal>rate</literal>=<value>rate</value></syntax>
+    <literal>rate</literal>=<value>rate</value>
+    [<literal>sync</literal>]</syntax>
 <default/>
 <context>http</context>
 
@@ -213,6 +214,16 @@
 For example, half-request per second is 30r/m.
 </para>
 
+<para id="limit_req_zone_sync">
+The <literal>sync</literal> parameter (1.15.3) enables
+<link doc="../stream/ngx_stream_zone_sync_module.xml" id="zone_sync">synchronization</link>
+of the shared memory zone.
+<note>
+The <literal>sync</literal> parameter is available as part of our
+<commercial_version>commercial subscription</commercial_version>.
+</note>
+</para>
+
 </directive>
 
 </section>