The recent upgrade did not deal with obsolete conffiles properly.
Please use the dpkg-maintscript-helper support provided by
dh_installdeb to remove these obsolete conffiles on upgrade.

https://www.debian.org/doc/debian-policy/ch-files.html#s-config-files
https://manpages.debian.org/man/1/dh_installdeb

   $ p=dkms ; adequate $p ; dpkg-query -W -f='${Conffiles}\n' $p | grep obsolete
   dkms: obsolete-conffile /etc/dkms/kernel_install.d_dkms
    /etc/dkms/kernel_install.d_dkms 15ac4d2d674fbc9715397b79edd1bc80 obsolete

This bug report brought to you by adequate:

https://bonedaddy.net/pabs3/log/2013/02/23/inadequate-software/

We believe that the bug you reported is fixed in the latest version of
dkms, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 996812@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Andreas Beckmann <anbe@debian.org> (supplier of updated dkms package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Fri, 27 May 2022 16:12:46 +0200
Source: dkms
Architecture: source
Version: 3.0.3-2
Distribution: unstable
Urgency: medium
Maintainer: Dynamic Kernel Modules Support Team <dkms@packages.debian.org>
Changed-By: Andreas Beckmann <anbe@debian.org>
Closes: 996812 1010883
Changes:
 dkms (3.0.3-2) unstable; urgency=medium
 .
   [ Andreas Beckmann ]
   * dkms-autopkgtest: Only install linux-headers-* packages matching the
     source version of linux-doc (a dependency generated by autodep8 for
     autopkgtest-pkg-dkms). Mixing different versions may fail if multiple
     distros (e.g. testing and unstable) are enabled and pinning is used.
     (Closes: #1010883)
   * Provide versioned virtual package dh-dkms.
   * Drop maintainer script code handling upgrades from versions predating
     squeeze/trusty.
   * Properly clean up ancient /etc/bash_completion.d/dkms.
   * Clean up ancient /etc/dkms/kernel_install.d_dkms.  (Closes: 996812)
   * Add debian/upstream/metadata.
   * Bump Standards-Version to 4.6.1, no changes needed.
   * Add myself to Uploaders.
 .
   [ Debian Janitor ]
   * Remove constraints unnecessary since buster.
     - dkms: Drop versioned constraint on coreutils in Depends.
Checksums-Sha1:
 431baa2abc882d9b315a586209fee86b77b6d3b4 2022 dkms_3.0.3-2.dsc
 378c37706004304dd7a84e54e32fc46b9012f759 20144 dkms_3.0.3-2.debian.tar.xz
 614fd9de0bdea9229a18da95a9699dc42564a0e1 5432 dkms_3.0.3-2_source.buildinfo
Checksums-Sha256:
 9db22ac1d267e980fcdd1e791ecca70eff4cb7ba79ccbf872ca2cfa7e3e1a375 2022 dkms_3.0.3-2.dsc
 3a1d399d4720b5be453a06c2143f73ea44733f2d5c18a48b833d980bc48caa32 20144 dkms_3.0.3-2.debian.tar.xz
 1e3515135c3b3abced3ac3d5602a2526063397dd1cd6dba740bd04a83e2097bf 5432 dkms_3.0.3-2_source.buildinfo
Files:
 173ad4bf67f93e718bc4a742e57bb95a 2022 kernel optional dkms_3.0.3-2.dsc
 e68ceb7f89566651f5fca0a126a0d78b 20144 kernel optional dkms_3.0.3-2.debian.tar.xz
 3848fb3b0135250fb027e149a80de8cf 5432 kernel optional dkms_3.0.3-2_source.buildinfo
-----BEGIN PGP SIGNATURE-----
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=W3xv
-----END PGP SIGNATURE-----