Failed upgrade to Buster from Strecth

Hello!

root@TorServer:~# dpkg -l libxml2
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name           Version                                        Architecture Description
+++-==============-==============================================-============-===============
==================
ii  libxml2:amd64  2.9.12+dfsg-0+0~20210621.9+debian9~1.gbp43e861 amd64        GNOME XML libra
ry
root@TorServer:~# apt show libxml2 -a
Package: libxml2
Version: 2.9.12+dfsg-0+0~20210621.9+debian9~1.gbp43e861
Status: install ok installed
Priority: optional
Section: libs
Maintainer: Debian XML/SGML Group <debian-xml-sgml-pkgs@lists.alioth.debian.org>
Installed-Size: 1,965 kB
Depends: libc6 (>= 2.15), libicu65 (>= 65.1-1~), liblzma5 (>= 5.1.1alpha+20120614), zlib1g (>= 1:1.2.3.3)
Homepage: http://xmlsoft.org
Download-Size: unknown
APT-Manual-Installed: no
APT-Sources: /var/lib/dpkg/status
Description: GNOME XML library

Package: libxml2
Version: 2.9.4+dfsg1-7+deb10u3
Priority: optional
Section: libs
Maintainer: Debian XML/SGML Group <debian-xml-sgml-pkgs@lists.alioth.debian.org>
Installed-Size: 1,903 kB
Depends: libc6 (>= 2.28), libicu63 (>= 63.1-1~), liblzma5 (>= 5.1.1alpha+20120614), zlib1g (>= 1:1.2.3.3)
Homepage: http://xmlsoft.org
Tag: role::shared-lib
Download-Size: 689 kB
APT-Sources: https://deb.debian.org/debian buster/main amd64 Packages
Description: GNOME XML library

It looks like there are two identical packages from different versions of Debian.

Indeed, so this needs to be downgraded to use the version shipped by Debian Buster:

apt install --reinstall --allow-downgrades libxml2=2.9.4+dfsg1-7+deb10u3
apt autopurge
dpkg -l | grep debian9

Reinstalling with downgrade did the trick. I did this for all packages that have the second version from Debian 10. I also purged the monodoc-browser package since there no version from deb10 (libjs-xmlextras mono-xsp4 mono-xsp4-base monodoc-http was installed instead).

Now there are no packages left from debian 9. And everything seems to work like a charm.
I will definitely not rush to upgrade to version 11.

Thanks for the help!

If you find time, have a look to our blog post on how to move to Bullseye. https://dietpi.com/blog/?p=811

Finally, great that it works now, and another good example good much trouble it caused that we did setup Ondrej’s PHP repository on Debian Stretch to make available PHP7.3. That way we were able to keep support on Stretch for Nextcloud many other web applications which dropped PHP7.0 support. We won’t do such anymore and instead help people to upgrade Debian to keep up support by their favourite software :slight_smile:.