diff --git a/doc/src/sgml/release-13.sgml b/doc/src/sgml/release-13.sgml
new file mode 100644
index 18e6497..0b1051b
*** a/doc/src/sgml/release-13.sgml
--- b/doc/src/sgml/release-13.sgml
*************** Author: Jeff Davis <jdavis@postgresql.or
*** 649,655 ****
  
         <para>
          Previously, hash aggregation was avoided if it was expected to use
!         more than <xref linkend="guc-work-mem"/> memory.
         </para>
        </listitem>
  
--- 649,658 ----
  
         <para>
          Previously, hash aggregation was avoided if it was expected to use
!         more than <xref linkend="guc-work-mem"/> memory.  To reduce the
!         likelihood of using disk storage for hash aggregation and attain
!         behavior similar to previous Postgres releases, increase <xref
!         linkend="guc-hash-mem-multiplier"/>.
         </para>
        </listitem>