diff --git a/doc/src/sgml/pgupgrade.sgml b/doc/src/sgml/pgupgrade.sgml
new file mode 100644
index b24c1e7..e4f90d9
*** a/doc/src/sgml/pgupgrade.sgml
--- b/doc/src/sgml/pgupgrade.sgml
*************** gmake prefix=/usr/local/pgsql.new instal
*** 256,263 ****
       so you might want to set authentication to <literal>trust</> in
       <filename>pg_hba.conf</>, or if using <literal>md5</> authentication,
       use a <filename>~/.pgpass</> file (see <xref linkend="libpq-pgpass">)
!      to avoid being prompted repeatedly for a password.  Also make sure
!      pg_upgrade is the only program that can connect to the clusters.
      </para>
     </step>
  
--- 256,262 ----
       so you might want to set authentication to <literal>trust</> in
       <filename>pg_hba.conf</>, or if using <literal>md5</> authentication,
       use a <filename>~/.pgpass</> file (see <xref linkend="libpq-pgpass">)
!      to avoid being prompted repeatedly for a password.
      </para>
     </step>
  
*************** pg_upgrade.exe
*** 336,341 ****
--- 335,343 ----
  
      <para>
       Obviously, no one should be accessing the clusters during the upgrade.
+      Consider using a non-default port number, e.g.  50432, for old
+      and new clusters to avoid unintended client connections during
+      the upgrade.     
      </para>
  
      <para>