On an IBM laptop.

 I get an unknown dist. notice:
...
Fetched 589 MB in 12min 35s (779 kB/s)                                                                                                                     
Extracting templates from packages: 100%
Preconfiguring packages ...
supported-versions: WARNING! Unknown distribution: devuan
debian found in ID_LIKE, treating as Debian
///

The upgrade wanted to change audio group from 18 to 29.
///

Eudev install complains that udev isn't installed:
Preparing to unpack .../5-eudev_3.2.7-6_amd64.deb ...
dpkg-query: package 'udev' is not installed
Use dpkg --info (= dpkg-deb --info) to examine archive files,
and dpkg --contents (= dpkg-deb --contents) to list their contents.
Unpacking eudev (3.2.7-6) over (3.2.2-13) ...
///

Since I use busybox init, I get this a few times:
invoke-rc.d: could not determine current runlevel
invoke-rc.d: WARNING: No init system and policy-rc.d missing! Defaulting to block.
///

There is some comflict between manpages and manpages-dev:
dpkg: considering deconfiguration of manpages-dev, which would be broken by installation of manpages ...
dpkg: yes, will deconfigure manpages-dev (broken by manpages)
Preparing to unpack .../24-manpages_4.16-2_all.deb ...
De-configuring manpages-dev (4.10-2) ...
Unpacking manpages (4.16-2) over (4.10-2) ...
///

Setting up iputils-ping (3:20180629-2) ...
Failed to set capabilities on file `/bin/ping' (Operation not supported)
The value of the capability argument is not permitted for a file. Or the file is not a regular (non-symlink) file
Setcap failed on /bin/ping, falling back to setuid
///

Unknown debian release:
Setting up postgresql-common (200+deb10u3) ...
Installing new version of config file /etc/apt/apt.conf.d/01autoremove-postgresql ...
supported-versions: WARNING: Unknown Debian release: 3
Replacing config file /etc/postgresql-common/createcluster.conf with new version
///

The upgrade didn't like my kernels/lilo setup:
Processing triggers for initramfs-tools (0.133+deb10u1) ...
update-initramfs: Generating /boot/initrd.img-4.9.0-8-amd64
I: The initramfs will attempt to resume from /dev/sda3
I: (UUID=65c4c336-60bf-4729-a4ac-b1899257ad99)
I: Set the RESUME variable to override this.
Added Memtest
Added 318
Added 418
Added 409c *
Added wifi
Added deb +
Processing triggers for libgdk-pixbuf2.0-0:amd64 (2.38.1+dfsg-1) ...
Processing triggers for menu (2.1.47+b1) ...
Errors were encountered while processing:
lilo
E: Sub-process /usr/bin/dpkg returned an error code (1)

So I removed the things that made it break:
dpkg -P initramfs-tools linux-image-4.9.0-8-amd64
///

 The line below starting with 11 is in red, it would be hard to read 
 for people with colour blindness:
Setting up postgresql-11 (11.5-1+deb10u1) ...
Creating new PostgreSQL cluster 11/main ...
/usr/lib/postgresql/11/bin/initdb -D /var/lib/postgresql/11/main --auth-local peer --auth-host md5
...
Ver Cluster Port Status Owner    Data directory              Log file
11  main    5433 down   postgres /var/lib/postgresql/11/main /var/log/postgresql/postgresql-11-main.log
update-alternatives: using /usr/share/postgresql/11/man/man1/postmaster.1.gz to provide /usr/share/man/man1/postmaster.1.gz (postmaster.1.gz) in auto mode
///

W: APT had planned for dpkg to do more than it reported back (3822 vs 3851).
Affected packages: gcc-6-multilib:amd64 gcc-multilib:amd64 lib32gcc-6-dev:amd64 libc6-dev-x32:amd64 libx32asan3:amd64 libx32atomic1:amd64 libx32cilkrts5:amd64 libx32gcc-6-dev:amd64 libx32gcc1:amd64 libx32gomp1:amd64 libx32itm1:amd64 libx32quadmath0:amd64 libx32stdc++6:amd64 libx32ubsan0:amd64
//////

reboot without problems
starting x worked fine
unfortunately emacs have stopped honouring the geometry option

Regards,
/Karl Hammar