Bug#947915: release-notes: Suggest cleaning up leftover *.dpkg-old etc. config files

["Karl O. Pinc" <kop@karlpinc.com>]

Package: release-notes
Severity: normal
Tags: patch

Hello,

Attached is a patch which suggests cleaning up unused config files
leftover from prior upgrades, the foo.dpkg-old and similar files,
before starting the new upgrade.

Regards,
Karl

-- System Information:
Debian Release: 10.2
  APT prefers stable
  APT policy: (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 4.19.0-6-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

diff --git a/en/upgrading.dbk b/en/upgrading.dbk
index b04a58e2..77f275fd 100644
--- a/en/upgrading.dbk
+++ b/en/upgrading.dbk
@@ -301,6 +301,17 @@ $ apt-forktracer | sort
     It is a good idea to <link linkend="obsolete">remove obsolete
     packages</link> from your system before upgrading.
   </para>
+  <para>
+    A previous upgrade can have left unused copies of configuration
+    files; <link linkend="configuration-changes">old versions</link>
+    of configuration files, versions supplied by the package
+    maintainers, etc.  Removing leftover files from previous upgrades,
+    before performing another upgrade, can avoid confusion.  Find such
+    leftover files with:
+  </para>
+  <screen>
+# find /etc -name '*.dpkg-*'
+  </screen>
 
   <section id="proposed-updates">
     <title>The proposed-updates section</title>