Comment 40 for bug 2039268

Since snapd has been released to {lunar,mantic}-updates, I tested an upgrade from lunar to mantic without any modifications, and all went well:

nr@clean-lunar-amd64:~$ sudo apt update && sudo apt install snapd -y
[sudo] password for nr:
Get:1 http://security.ubuntu.com/ubuntu lunar-security InRelease [109 kB]
Hit:2 http://archive.ubuntu.com/ubuntu lunar InRelease
Get:3 http://archive.ubuntu.com/ubuntu lunar-updates InRelease [109 kB]
Get:4 http://security.ubuntu.com/ubuntu lunar-security/main amd64 DEP-11 Metadata [7,412 B]
Get:5 http://security.ubuntu.com/ubuntu lunar-security/universe amd64 DEP-11 Metadata [32.0 kB]
Get:6 http://archive.ubuntu.com/ubuntu lunar-updates/main Sources [155 kB]
Get:7 http://archive.ubuntu.com/ubuntu lunar-updates/main amd64 Packages [503 kB]
Get:8 http://archive.ubuntu.com/ubuntu lunar-updates/main amd64 DEP-11 Metadata [81.1 kB]
Get:9 http://archive.ubuntu.com/ubuntu lunar-updates/universe i386 Packages [674 kB]
Get:10 http://archive.ubuntu.com/ubuntu lunar-updates/universe amd64 Packages [814 kB]
Get:11 http://archive.ubuntu.com/ubuntu lunar-updates/universe amd64 DEP-11 Metadata [71.5 kB]
Fetched 2,555 kB in 2s (1,477 kB/s)
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
1 package can be upgraded. Run 'apt list --upgradable' to see it.
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following packages were automatically installed and are no longer required:
  linux-headers-6.2.0-26 linux-headers-6.2.0-26-generic
  linux-image-5.19.0-46-generic linux-image-6.2.0-26-generic
  linux-modules-5.19.0-46-generic linux-modules-6.2.0-26-generic
  linux-modules-extra-5.19.0-46-generic linux-modules-extra-6.2.0-26-generic
Use 'sudo apt autoremove' to remove them.
The following packages will be upgraded:
  snapd
1 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 26.2 MB of archives.
After this operation, 4,096 B of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu lunar-updates/main amd64 snapd amd64 2.59.1+23.04ubuntu1.2 [26.2 MB]
Fetched 26.2 MB in 2s (14.5 MB/s)
(Reading database ... 248469 files and directories currently installed.)
Preparing to unpack .../snapd_2.59.1+23.04ubuntu1.2_amd64.deb ...
Unpacking snapd (2.59.1+23.04ubuntu1.2) over (2.59.1+23.04ubuntu1.1) ...
Setting up snapd (2.59.1+23.04ubuntu1.2) ...
snapd.failure.service is a disabled or a static unit not running, not starting i
t.
snapd.snap-repair.service is a disabled or a static unit not running, not starti
ng it.
Failed to restart snapd.mounts-pre.target: Operation refused, unit snapd.mounts-
pre.target may be requested by dependency only (it is configured to refuse manua
l start/stop).
See system logs and 'systemctl status snapd.mounts-pre.target' for details.
Could not execute systemctl: at /usr/bin/deb-systemd-invoke line 145.
Processing triggers for gnome-menus (3.36.0-1.1ubuntu1) ...
Processing triggers for man-db (2.11.2-1) ...
Processing triggers for dbus (1.14.4-1ubuntu1) ...
Processing triggers for mailcap (3.70+nmu1ubuntu1) ...
Processing triggers for desktop-file-utils (0.26-1ubuntu5) ...

nr@clean-lunar-amd64:~$ do-release-upgrade -d
Checking for a new Ubuntu release

= Welcome to Ubuntu 23.10 'Mantic Minotaur' =

The Ubuntu team is proud to announce Ubuntu 23.10 'Mantic Minotaur'.

[...]

Processing snap replacements

refreshing snap core22

installing snap firmware-updater

refreshing snap gnome-42-2204

refreshing snap gtk-common-themes

refreshing snap snap-store

refreshing snap snapd-desktop-integration

refreshing snap firefox

Searching for obsolete software
Reading state information... Done

Remove obsolete packages?

90 packages are going to be removed.

 Continue [yN] Details [d]y
Fetched 0 B in 0s (0 B/s)

[...]

System upgrade is complete.

Restart required

To finish the upgrade, a restart is required.
If you select 'y' the system will be restarted.

Continue [yN] N
nr@clean-lunar-amd64:~$ snap list
Name Version Rev Tracking Publisher Notes
bare 1.0 5 latest/stable canonical\u2713 base
core20 20230801 2015 latest/stable canonical\u2713 base
core22 20230801 864 latest/stable canonical\u2713 base
firefox 118.0-1 3166 latest/stable/\u2026 mozilla\u2713 -
firmware-updater 0+git.e8771be 109 latest/stable/\u2026 canonical\u2713 -
gnome-3-38-2004 0+git.efb213a 143 latest/stable canonical\u2713 -
gnome-42-2204 0+git.ff35a85 141 latest/stable/\u2026 canonical\u2713 -
gtk-common-themes 0.1-81-g442e511 1535 latest/stable/\u2026 canonical\u2713 -
snap-store 41.3-71-g709398e 959 latest/stable/\u2026 canonical\u2713 -
snapd 2.60.4 20290 latest/stable canonical\u2713 snapd
snapd-desktop-integration 0.9 83 latest/stable/\u2026 canonical\u2713 -