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 -