diff --git a/doc/src/sgml/protocol.sgml b/doc/src/sgml/protocol.sgml
index 9178c779ba..00c593f1af 100644
--- a/doc/src/sgml/protocol.sgml
+++ b/doc/src/sgml/protocol.sgml
@@ -2731,14 +2731,24 @@ The commands accepted in replication mode are:
+        <para>
+          For <literal>gzip</literal> the compression level should be an