Here is what happens when taking the default except where just hitting enter would abort the upgrade.
Logging all decisions (except the do you really want to do that inside ssh)
...
Xenial -> Bionic
3 installed packages are no longer supported by Canonical. You can
still get support from the community.
4 packages are going to be removed. 227 new packages are going to be
installed. 436 packages are going to be upgraded.
You have to download a total of 350 M. This download will take about
1 minute with your connection.
Installing the upgrade can take several hours. Once the download has
finished, the process cannot be canceled.
Here is what happens when taking the default except where just hitting enter would abort the upgrade.
Logging all decisions (except the do you really want to do that inside ssh)
...
Xenial -> Bionic
3 installed packages are no longer supported by Canonical. You can
still get support from the community.
4 packages are going to be removed. 227 new packages are going to be
installed. 436 packages are going to be upgraded.
You have to download a total of 350 M. This download will take about
1 minute with your connection.
Installing the upgrade can take several hours. Once the download has
finished, the process cannot be canceled.
Continue [yN] Details [d]
y
39 packages are going to be removed.
Continue [yN] Details [d]d
...
Remove: initscripts insserv libbind9-140 libcryptsetup4 5-minimal 5-stdlib libreadline6 libxtables11 python3.5
libdns-export162 libdns162 libevent-2.0-5 libgdbm3 libicu55
libisc-export160 libisc160 libisccc140 libisccfg140 libjson-c2
liblwres141 libmpfr4 libpng12-0 libprocps4 libpython3.
libpython3.
python3.5-minimal sysv-rc
Remove (was auto installed) cgmanager libboost- iostreams1. 58.0 random1. 58.0 libboost- system1. 58.0 libboost- thread1. 58.0 headers- 4.4.0-210 linux-headers- 4.4.0-210- generic pm-utils
libboost-
libcgmanager0 libnih-dbus1 libpython3.5 libx86-1 libxen-4.6
linux-
vbetool
Continue [yN] Details [d]
N
Restart required
(has to be done to be able to enter the next upgrade)
Continue [yN]
Y
---
# Now Bionic to Focal
16 installed packages are no longer supported by Canonical. You can
still get support from the community.
3 packages are going to be removed. 195 new packages are going to be
installed. 603 packages are going to be upgraded.
You have to download a total of 453 M. This download will take about
1 minute with your connection.
Installing the upgrade can take several hours. Once the download has
finished, the process cannot be canceled.
Continue [yN] Details [d]
Remove: btrfs-tools command- not-found- data gcc-5-base gcc-6-base
libffi6 libhogweed4 liblvm2app2.2 liblvm2cmd2.02 libnettle6 libnih1
libplymouth4 libvirt-bin ureadahead
Remove (was auto installed) augeas-lenses bridge-utils cgmanager iostreams1. 58.0 libboost- random1. 58.0 system1. 58.0 libboost- thread1. 58.0 libbrlapi0.6 6-minimal libpython3.6-stdlib libreadline7 4.15.0- 213 headers- 4.15.0- 213-generic linux-headers- 4.4.0-210 headers- 4.4.0-210- generic linux-image- 4.4.0-210- generic modules- 4.4.0-210- generic nplan perl-modules-5.26 pm-utils asn1crypto python3-pam python3.6 python3.6-minimal vbetool
ebtables efibootmgr gcc-8-base libargon2-0 libaugeas0 libbind9-160
libbluetooth3 libboost-
libboost-
libcgmanager0 libdns-export1100 libdns1100 libevent-2.1-6 libgdbm5
libicu60 libip4tc0 libip6tc0 libiptc0 libirs160 libisc-export169
libisc169 libisccc160 libisccfg160 libjson-c3 liblwres160 libnetcf1
libnih-dbus1 libntfs-3g88 libperl5.26 libprocps6 libpython3.5
libpython3.6 libpython3.
libsdl1.2debian libvpx5 libx86-1 libxen-4.6 libxen-4.9
libxenstore3.0 libxentoolcore1 linux-headers-
linux-
linux-
linux-
python3-
xdelta3
Continue [yN] Details [d]
N
Restart required
Continue [yN]
y
$ apt-cache policy libvirt-bin libvirt-clients; virsh -v dpkg/status archive. ubuntu. com/ubuntu focal-updates/main amd64 Packages security. ubuntu. com/ubuntu focal-security/main amd64 Packages dpkg/status archive. ubuntu. com/ubuntu focal/main amd64 Packages
libvirt-bin:
Installed: 4.0.0-1ubuntu8.21
Candidate: 4.0.0-1ubuntu8.21
Version table:
*** 4.0.0-1ubuntu8.21 100
100 /var/lib/
libvirt-clients:
Installed: 6.0.0-0ubuntu8.16
Candidate: 6.0.0-0ubuntu8.16
Version table:
*** 6.0.0-0ubuntu8.16 500
500 http://
500 http://
100 /var/lib/
6.0.0-0ubuntu8 500
500 http://
6.0.0
# Now Focal to Jammy
13 installed packages are no longer supported by Canonical. You can
still get support from the community.
10 packages are going to be removed. 146 new packages are going to be
installed. 757 packages are going to be upgraded.
You have to download a total of 691 M. This download will take about
2 minutes with your connection.
Installing the upgrade can take several hours. Once the download has
finished, the process cannot be canceled.
Continue [yN] Details [d]
y
Remove obsolete packages?
120 packages are going to be removed.
Removing the packages can take several hours.
Continue [yN] Details [d]d
Remove: e2fslibs fonts-ubuntu- font-family- console libcomerr2
libfwupdplugin1 libidn11 libldap-2.4-2 libreadline5 libsepol1 lxd
lxd-client
Remove (was auto installed) augeas-lenses bridge-utils cgmanager crda iostreams1. 58.0 libboost- iostreams1. 71.0 random1. 58.0 libboost- system1. 58.0 libboost- thread1. 58.0 thread1. 71.0 libbrlapi0.6 libbrlapi0.7 libcanberra0 pixbuf- xlib-2. 0-0 libgdk-pixbuf2.0-0 libhogweed5 libicu60 6-minimal libpython3.6-stdlib libpython3.8 8-minimal libpython3.8-stdlib libreadline7 librest-0.7-0 daemon- driver- storage- rbd libvorbisfile3 libvpx5 libvpx6 4.15.0- 213 headers- 4.15.0- 213-generic linux-headers- 4.4.0-210 headers- 4.4.0-210- generic linux-headers- 5.4.0-169 headers- 5.4.0-169- generic linux-image- 4.15.0- 213-generic image-4. 4.0-210- generic linux-modules- 4.15.0- 213-generic modules- 4.4.0-210- generic modules- extra-4. 15.0-213- generic modules- extra-5. 4.0-169- generic lz4 nplan perl-modules-5.30 requests- unixsocket python3-simplejson python3.6 theme-freedeskt op vbetool xdelta3
cryptsetup-run ebtables efibootmgr gcc-10-base gcc-8-base
libargon2-0 libaugeas0 libbind9-160 libbluetooth3
libboost-
libboost-
libboost-
libcbor0.6 libcgmanager0 libdns-export1100 libdns-export1109
libdns1100 libevent-2.1-6 libevent-2.1-7 libffi7 libfl2 libgdbm5
libgdk-
libicu66 libip4tc0 libip6tc0 libiptc0 libirs160 libisc-export169
libisc169 libisccc160 libisccfg160 libjson-c3 libjson-c4 libltdl7
liblwres160 libnetcf1 libnettle7 libnih-dbus1 libntfs-3g88
libntfs-3g883 libperl5.30 libprocps6 libpython3.5 libpython3.6
libpython3.
libpython3.
libsdl1.2debian libsoup-gnome2.4-1 libssl1.1 libtdb1 liburcu6
libvirt-
libwebp6 libx86-1 libxen-4.6 libxen-4.9 libxenstore3.0
libxentoolcore1 libxmlb1 linux-headers-
linux-
linux-
linux-
linux-
linux-
linux-
linux-
pm-utils python3-asn1crypto python3-entrypoints python3-pam
python3-
python3.6-minimal python3.8 python3.8-minimal sharutils
sound-
Continue [yN] Details [d]
N
Restart required
Continue [yN]
y
$ apt-cache policy libvirt-bin libvirt-clients; virsh -v dpkg/status archive. ubuntu. com/ubuntu jammy-updates/main amd64 Packages dpkg/status 0.0-1ubuntu7. 5 500 security. ubuntu. com/ubuntu jammy-security/main amd64 Packages archive. ubuntu. com/ubuntu jammy/main amd64 Packages
libvirt-bin:
Installed: 4.0.0-1ubuntu8.21
Candidate: 4.0.0-1ubuntu8.21
Version table:
*** 4.0.0-1ubuntu8.21 100
100 /var/lib/
libvirt-clients:
Installed: 8.0.0-1ubuntu7.8
Candidate: 8.0.0-1ubuntu7.8
Version table:
*** 8.0.0-1ubuntu7.8 500 (phased 10%)
500 http://
100 /var/lib/
8.
500 http://
8.0.0-1ubuntu7 500
500 http://
8.0.0
So, if paying attention and saying "no" there, it actually is just fine.