server in <literal>node1</literal>, e.g.:
<programlisting>
pg_ctl -D /opt/PostgreSQL/data1 stop
</programlisting>
       </para>
      </step>

      <step>
       <para>
        Initialize <literal>data1_upgraded</literal> instance by using the
        required newer version.
       </para>
      </step>

      <step>
       <para>
        Upgrade the publisher <literal>node1</literal>'s server to the
        required newer version, e.g.:
<programlisting>
pg_upgrade
        --old-datadir "/opt/PostgreSQL/postgres/17/data1"
        --new-datadir "/opt/PostgreSQL/postgres/18/data1_upgraded"
        --old-bindir "/opt/PostgreSQL/postgres/17/bin"
        --new-bindir "/opt/PostgreSQL/postgres/18/bin"
</programlisting>
       </para>
      </step>

      <step>
       <para>
        Start the upgraded publisher server in <literal>node1</literal>, e.g.:
<programlisting>
pg_ctl -D /opt/PostgreSQL/data1_upgraded start -l logfile
</programlisting>
       </para>
      </step>

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

      <step>
       <para>
        On <literal>node2</literal>, create any tables that were created in
        the upgraded publisher <literal>node1</literal> server between
        <xref linkend="two-node-cluster-disable-subscriptions-node2"/>
        and now, e.g.:
<programlisting>
/* node2 # */ CREATE TABLE distributors (did integer PRIMARY KEY, name varchar(40));
</programlisting>
       </para>
      </step>

      <step>
       <para>
        Enable all the subscriptions on <literal>node2</literal> that are
        subscribing the changes from <literal>node1</literal> by using
        <link linkend="sql-altersubscription-params-enable"><command>ALTER SUBSCRIPTION ... ENABLE</command></link>,
        e.g.:
<programlisting>
/* node2 # */ ALTER SUBSCRIPTION sub1_node1_node2 ENABLE;
</programlisting>
       </para>
      </step>

      <step>
       <para>
        Refresh the <literal>node2</literal> subscription's publications using
        <link linkend="sql-altersubscription-params-refresh-publication"><command>ALTER SUBSCRIPTION ... REFRESH PUBLICATION</command></link>,
        e.g.:
<programlisting>
/* node2 # */ ALTER SUBSCRIPTION sub1_node1_node2 REFRESH PUBLICATION;
</programlisting>
       </para>
      </step>
     </procedure>

     <note>
      <para>
       In the steps described above, the publisher is upgraded first, followed
       by the subscriber. Alternatively, the user can use similar steps to
       upgrade the subscriber first, followed by the publisher.
      </para>
     </note>
    </sect3>

    <sect3 id="steps-cascaded-logical-replication-cluster">
     <title>Steps to upgrade a cascaded logical replication cluster</title>
     <para>
      Let's say we have a cascaded logical replication setup
      <literal>node1</literal>-><literal>node2</literal>-><literal>node3</literal>.
      Here <literal>node2</literal> is subscribing the changes from
      <literal>node1</literal> and <literal>node3</literal> is subscribing