How to stay on Thunderbird 115

Keeping the Thunderbird version you are using stuck at 115 when it really wants to upgrade you to a newer version is less straightforward than one would hope.

Downloading

1. Go to the Thunderbird release archive.
2. Find the highest-numbered release whose number starts with "115." and open it. At the time this page was written, that was 115.15.0, and the link above will take you there, but check carefully to make sure a newer release hasn't come out since then.
3. Click on the appropriate subdirectory for your OS:
   • "linux-x86_64" is 64-bit Linux
   • "win64" is 64-bit Windows
   • "mac" is macOS
   • "linux-i686" is 32-bit Linux (unlikely to be what you want)
   • "win32" is 32-bit Windows (unlikely to be what you want)
4. Click on your language.
5. Download and save the installer file:
   • for Linux, it's the .tar.bz2 file
   • for Windows, you can use either the .msi or .exe file as you prefer
   • for macOS, choose whether to use the .dmg or .pkg as described below

Installing

Linux

1. Uninstall the OS Thunderbird package so you don't accidentally run it. (You can reinstall it later when all this blows over.)
2. Download and save the Linux Thunderbird tar file as described above.
3. Make sure there isn't a directory called "thunderbird" in your home directory (because if there is, you're about to overwrite it).

4. In a terminal window, run these commands:

    cd ~
    tar xf [full path of the saved tar file]
   

At this point you can just stop, and from now on whenever you want to run launch Thunderbird you can run ~/thunderbird/thunderbird in a terminal window. However, read on if you want to make it launchable as a desktop application.

Note: these instructions work in GNOME, and I think they will work in other desktop environments that follow the desktop file standard, but I'm not certain.

Create a file called Thunderbird 115.desktop and put this in it, substituting the path to your home directory in place of /home/example:

[Desktop Entry]
Name=Thunderbird 115
Comment=Read/Write Mail/News with Thunderbird
GenericName=Mail Client
Exec=/home/example/thunderbird/thunderbird %u
Terminal=false
X-MultipleArgs=false
Type=Application
Version=1.0
Icon=/home/example/thunderbird/chrome/icons/default/default256.png
Categories=Network;Email;News;GTK;
MimeType=message/rfc822;x-scheme-handler/mailto;text/calendar;text/x-vcard;
StartupWMClass=thunderbird-default
StartupNotify=true
Keywords=EMail;E-mail;Contact;Addressbook;News;
Actions=Compose;Contacts

[Desktop Action Compose]
Name=Compose New Message
Exec=/home/example/thunderbird/thunderbird -compose

[Desktop Action Contacts]
Name=Contacts
Exec=/home/example/thunderbird/thunderbird -addressbook

Create the directory ~/.local/share/applications if it doesn't already exist.

Move the Thunderbird 115.desktop file into that directory.

Log out and log back in again.

Windows

Download the installer as described above.

Run the installer and I think it will overwrite any newer version of Thunderbird you already had installed (if not, let me know and I'll update these instructions!).

MacOS

You can either install Thunderbird in your global Applications folder or just put the application on your desktop and double-click it from there to run it.

To put it on your desktop:

1. Download the .dmg file as described above.
2. Double-click the .dmg file to mount it.
3. Double-click the mounted DMG volume on your desktop to open it.
4. Drag and drop the Thunderbird app from the open folder onto your desktop.
5. Drag and drop the mounted DMG volume to the Trash.
6. If you don't want to accidentally run the version of Thunderbird installed in your Applications folder, then open that folder and drag Thunderbird from there to the Trash.

To put it in the global Applications folder:

• Option 1: download the .pkg file as described above and then run it. I believe it will replace any version of Thunderbird already installed in your Applications folder. If not, let me know and I will update these instructions!

• Option 2: download the .dmg file, mount and open it as described above, and then drag and drop the Thunderbird icon into the Applications folder showed in the open DMG folder.

Downgrading your profile so you don't have to recreate it

If you've already been upgraded to Thunderbird 128 and you're downgrading to Thunderbird 115, then by default Thunderbird won't let you use your existing profile with Thunderbird 115 because it doesn't allow profiles to go backward by default. If it's straightforward for you to create a new profile from scratch, you can just do that. However, if you've got a lot of customizations in your existing profile and you don't want to have to recreate it, you can force Thunderbird to "downgrade" your profile back to Thunderbird 115.

• On Linux, run ~/thunderbird/thunderbird --allow-downgrade in a terminal window.
• On Windows, run "C:\Program Files\Mozilla Thunderbird\thunderbird.exe" --allow-downgrade in a command window.
• On macOS, if you put Thunderbird 115 into the global Applications folder, run open -a /Applications/Thunderbird.app --args --allow-downgrade. If you put it on your Desktop, use /Users/[your username]/Desktop instead of /Applications.

You only need to do this the first time you open your profile in Thunderbird after you've downgraded to Thunderbird 115.

Disabling updates

Open the Settings tab in Thunderbird, make sure "General" is selected on the left, scroll down to the "Updates" section, and select "Check for updates, but let me choose whether to install them".

Getting notified about TB115 updates (including important security fixes!)

You should install new versions of Thunderbird 115 as they come out so that you get security fixes.

To find out about them, you can follow the RSS feed of Thunderbird updates which Mozilla publishes at https://www.thunderbird.net/thunderbird/releases/atom.xml. You can subscribe to this feed in any RSS feeder, including in Thunderbird itself.

You will have to repeat the installation instructions above to install each new Thunderbird 115 release.