Some info will help. - click help>about and share what version you are using - now, click settings>general and scroll down to the Updates section and click the button that shows update history and report what the prior version was.

That may help, as a version installed years ago would not upgrade to an unsupported version. An unsupported version can only be installed from other distribution sources than Thunderbird's. Knowing that may help is advising how to avoid this. Thank you.

This is the link to other question - https://support.mozilla.org/en-US/questions/1467517

It's best to continue the conversation in the original question.

But it would be helpful if you tell us what version you are using at the moment.

All update info will be here :

• Settings > General
• scroll down to 'Updates' section
• clickon 'Show update history'
• Post an image of what it says.

Info also here: In Thunderbird Help > About Thunderbird What version does it say you are using ?

You can also find information here: Help > Troubleshooting Information

Thanks for getting back to me. It looks like the version number is 131.0. The update history says that there were several 128.3 update attempts in the last week that could not be installed as the patch failed? Thank you. Tony I

Earlier, I misspoke. Version 131.0 had earlier not been on the official page. My apologies for any confusion. The 131.0 is safe to use, but may have a few bugs. It's as safe as beta, and many use beta daily. If you can live with that, no change is necessary.

It looks like the version number is 131.0.

Version 131.0 | Released October 1, 2024 Thunderbird version 131.0 is available for testing purposes only.

Maybe you have some updater software on your computer and it detected that particular update and therefore updated Thunderbird.

Many people have and use Updater Software so auto updates occur in programs. However, Updater Software has no knowledge about what is the correct version to use when it comes to updating. When major releases occur, Thunderbird never offers an update to that major release immediately and usually updates a current version to within same number eg: 128.1.0 update to 128.2.0 etc

Please check your Updater Software and make sure Thunderbird is not one the apps it can auto update. You really need to have Thunderbird in full control of updates.

The latest release is Version 128.3.0esr.

The version you are currently using has a number which is greater than the current release. That means it doesn't like to go backwards, so basically there is no auto update to a version that goes backwards !

If you want to use the current release version - You can do this - I'm assuming you are using a Windows OS.

In Thunderbird Help > Troubleshooting Information Under 'Application Basics' - half way is Profile Folder - click on 'Open Folder'

A new window opens showing the contents of your profile name folder.

Exit Thunderbird now - this is important.

Look for 'compatibility.ini' file and delete it.

At this point - you could create abackup - just in case :) Go up directory to 'Profiles' folder Go up directory to 'Thunderbird' folder Go up directory to 'Roaming' folder Copy the 'Thunderbird' folder Paste it into another location - eg: D: drive or external drive or if still unsure - create a folder on desktop and call it 'TB-Backup' and then paste the copied 'Thunderbird folder into that folder.

Now uninstall Thunderbird - just the program. in Windows search type: uninstall select 'Add or Remove Programs' Locate Thunderbird 131.0 click on uninstall

Now to get new release: Go to this link: https://www.thunderbird.net/en-US/thunderbird/all/

Make sure to select correct 'Locale' as the US may be the default. Channel : 'Thunderbird Extended Support Release' OS: Windows

Click on 'Download' Then run and install.

When you restart Thunderbird a new 'compatibity.ini' file gets created. It should restart and use the same profile.

Thank you SOOOO much for the replies on 1:07 and 1:09. Very helpful!

I have the same problem. My thunderbird silently was updated from 128 to 131. I now tried to downgrade to 128, but I get the answer that the profile is not compatible anymore. I then tried to re-install 131, but now it comes as a beta version that does not recognize my profile. Any idea how can I restore a thunderbird version that uses my profile, and then properly downgrade to a working version, aka 128? I really would like to avoid to have to reconfigure all of my accounts.

Please review Toad-Hall's detailed steps to do that. What you are using is a prerelease of what will soon be a supported monthly version. That is, reverting to 128 isn't mandatory for a reliable client. Toad-Hall's instructions will take you safely to 128.