diff --git a/xml/en/docs/http/ngx_http_ssl_module.xml b/xml/en/docs/http/ngx_http_ssl_module.xml
index 5334fd02..4aca70c4 100644
--- a/xml/en/docs/http/ngx_http_ssl_module.xml
+++ b/xml/en/docs/http/ngx_http_ssl_module.xml
@@ -447,7 +447,8 @@ might result in unexpected behavior.
 <para>
 Specifies a <value>file</value> with revoked certificates (CRL)
 in the PEM format used to <link id="ssl_verify_client">verify</link>
-client certificates.
+client certificates. If provided, a CRL must be included for each
+certificate in the certificate chain.
 </para>
 
 </directive>