linkend="sql-altersubscription-params-refresh-publication"><command>ALTER SUBSCRIPTION ... REFRESH PUBLICATION</command></link>,
        e.g.:
<programlisting>
/* node1 # */ ALTER SUBSCRIPTION sub1_node2_node1 REFRESH PUBLICATION;
</programlisting>
       </para>
      </step>

      <step id="circular-cluster-disable-sub-node1">
       <para>
        Disable all the subscriptions on <literal>node1</literal> that are
        subscribing the changes from <literal>node2</literal> by using
        <link linkend="sql-altersubscription-params-disable"><command>ALTER SUBSCRIPTION ... DISABLE</command></link>,
        e.g.:
<programlisting>
/* node1 # */ ALTER SUBSCRIPTION sub1_node2_node1 DISABLE;
</programlisting>
       </para>
      </step>

      <step>
       <para>
        Stop the server in <literal>node2</literal>, e.g.:
<programlisting>
pg_ctl -D /opt/PostgreSQL/data2 stop
</programlisting>
       </para>
      </step>

      <step>
       <para>
        Initialize <literal>data2_upgraded</literal> instance by using the
        required newer version.
       </para>
      </step>

      <step>
       <para>
        Upgrade the <literal>node2</literal>'s server to the required
        new version, e.g.:
<programlisting>
pg_upgrade
        --old-datadir "/opt/PostgreSQL/postgres/17/data2"
        --new-datadir "/opt/PostgreSQL/postgres/18/data2_upgraded"
        --old-bindir "/opt/PostgreSQL/postgres/17/bin"
        --new-bindir "/opt/PostgreSQL/postgres/18/bin"
</programlisting>
       </para>
      </step>

      <step>
       <para>
        Start the upgraded server in <literal>node2</literal>, e.g.:
<programlisting>
pg_ctl -D /opt/PostgreSQL/data2_upgraded start -l logfile
</programlisting>
       </para>
      </step>

      <step>
       <para>
        Enable all the subscriptions on <literal>node1</literal> that are
        subscribing the changes from <literal>node2</literal> by using
        <link linkend="sql-altersubscription-params-enable"><command>ALTER SUBSCRIPTION ... ENABLE</command></link>,
        e.g.:
<programlisting>
/* node1 # */ ALTER SUBSCRIPTION sub1_node2_node1 ENABLE;
</programlisting>