It had been a little less than a month since circulated Something more than rumors, but it has already been confirmed. Ubuntu 24.04 will add a new snap package by default when the stable version arrives. In fact, the change has already been made in the Daily Build. Thunderbird, one of the most popular email clients available for Linux and developed by Mozilla, follows the path of Firefox and will only be available as snap packages.
In the previous message you can read: «Update to thunderbird snap. Starting with Ubuntu 24.04, all new releases of thunderbird are only available through the snap package for Ubuntu users. This package update will transition your system through snap upon installation. It is recommended to close all thunderbird windows before proceeding with the update«. After making the change, in the case of the Daily Build, Thunderbird is removed and reinstalled, this time as snap pack.
At the moment there is no news of a Thunderbird as a Debian package
Right now it is not known what the future will hold in the medium term, beyond the fact that Canonical will not offer the mail client as a Debian package in the same way that happened before with the Chromium and Firefox browsers. Therefore, and until an alternative is published, it will be the only option. In the future it is likely that Mozilla will upload it to the repository where we can download Firefox and give instructions to install it so that the operating system does not revert the changes when trying to update to a future version.
If we look back in time, the first to make the change will be Ubuntu in its main version, the one that uses GNOME (Kubuntu has also already made the change), and some time later the rest of the official flavors will follow. Currently there are none that use Firefox in its DEB version. Yes it is possible in KDE neon, but because it is not under Canonical in any sense, and the KDE developers add the Mozilla repository by default.
The snap family is growing.