I regret your decision, as thousands like the new Thunderbird. BUT, it's your decision. To downgrade, Try:

   Exit Thunderbird if running.
   click windows key and 'r' key
   Enter: thunderbird.exe -P --allow-downgrade
   click on 'OK' 

The latest version prior to 115 was 102

Thank you for your response.

First of all, I have an old-fashioned keyboard that doesn't have a Windows key (out of choice -- it was in the way). Can you give me the steps using the Windows menus?

You seem to be saying that this downgrade can be done easily. If so, I find that remarkable. In the past, it was necessary to download an old version.

So "thunderbird.exe -P -- allow-downgrade" is precisely what I must type to downgrade (once I get a command line)?

Thank you.

Oh, it just occurred to me that "r" may mean "Run". If that's so, I know how to get to the Run prompt.

IT DIDN'T WORK using the Run prompt. Version 115.5.1 is still active.

Of course you need to install an old version, and despite Davids good feelings the downgrade process rarely goes smoothly in my experience. Something is usually lost.

I am still battling on with 115. It is ugly and cumbersome, but security updates are just so important to me.

I do strongly suggest you offer feedback on the link on Thunderbird help menu. This support forum is a peer site and no one that actually makes decision about Thunderbird ever comes here.

I don't believe that version 102 is insecure. I used Eudora for a decade after it was discontinued, and I never got a virus.

So David's steps are just nonsense?

If I have to install an old version, why not just install version 102?

Matt, I hear what you said, but it doesn't help me in my immediate situation.

- Where do I get version 102? - Do I uninstall version 115 before installing version 102? - Won't the 102 installation file default to version 115? - If not, can I install 102 OVER 115? - Can I have two versions on my computer at the same time? - Do I follow David's steps at ANY point in the process? - What will happen to my configuration files?

I need specific help, Matt.

I don't believe that version 102 is insecure. I used Eudora for a decade after it was discontinued, and I never got a virus.

No I never said that at all. I said security updates were important to me. These fixes to be specific. https://www.mozilla.org/en-US/security/known-vulnerabilities/thunderbird/

So David's steps are just nonsense?

I did not say that either.

If I have to install an old version, why not just install version 102?

Why not indeed.

Matt, I hear what you said, but it doesn't help me in my immediate situation. - Where do I get version 102?

Same place as every previous version of Thunderbird is archived. http://ftp.mozilla.org/pub/thunderbird/releases/ I covered this back in 2011 on my blog https://thunderbirdtweaks.blogspot.com/2011/07/i-want-old-version-of-thunderbird.html

- Do I uninstall version 115 before installing version 102? - Won't the 102 installation file default to version 115? - If not, can I install 102 OVER 115?

It makes little difference at all what you do. Uninstall or not. Your choice. If you don't windows says you have both versions installed when you don't. That is about all I can say.

- Can I have two versions on my computer at the same time?

Of course. As long as they are installed in different location (you have to do the advanced thing so as set an install location for the version)

- Do I follow David's steps at ANY point in the process?

Of course, you just install the old version first. Which will refuse to use your old profile and attempts to set up a new one until you follow Davids instructions.

- What will happen to my configuration files?

They will remain unchanged. So if they were updated for 115 then those data changes will be lost in 102, as will the data the files contained. That is why I tell people do not do it. But who am I to argue with a Eudora user with an antivirus program.

I need specific help, Matt.

You will need to understand the profile and profile managers as well as profile per install. I have no intention of offering step by step instruction that will take you back, I really don't have time for the missteps and the data loss questions that will follow. https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-thunderbird-profiles and profile per install which is what you are trying to defeat to use your profile with an old version as well as https://support.mozilla.org/en-US/kb/dedicated-profile-thunderbird-installation

Fundamentally if you need more information than that, then going backwards is not for you. You do not have the technical skills to execute it without issues. Really I suggest you work on making the new interface as good and comfortable as you can and get on with life. Most (not all) of the changes can be turned off or modified to make things close to what you feel is normal. I even got the menu on the top and the toolbar followed by the tabs.

Thank you, Matt, although you sound somewhat begrudging, a curious attitude given that you choose to do this work (without pay, I understand). The truth is that I have worked with the profile files before -- several times, in fact -- but once I've finished the project in question, all the steps go out of my head. I hate having to familiarize myself with it all over again.

However, I decided to see if I could make this horrible version work. I managed to create a little more space by eliminating a couple elements, but the huge gap in the middle of the program (shown in the picture) remains. They could have made all that stuff smaller if they had tried, but they didn't. Since I can access all those functions via the menu, I would like to close up that space altogether.

I've discovered that I can eliminate the icons, but it is really the text which is taking up all the space. Is there any setting I can change (in the profile files if necessary) that will keep the icons, and eliminate the text (which I can get from the email itself). Perhaps someone has already made an add-on that will do something like that. Any ideas?

Let me point out that all of that wasted vertical space in this bar alone (as shown in the screen shot) is there despite my using the Dense mode. Things like this are what make me think that the developers are not actually using the program. I NEED all the space that that bar is gobbling up.

Thank you.

Okay, I just discovered that I already have an add-on installed that closes up that space a bit (it just wasn't activated), but it isn't working the way it did in version 102 -- specifically, the icons don't show. I'll contact the developer of the add-on. Maybe they can update it.

However, there is still a lot more wasted space in the interface than in 102, and I find that really annoying. I don't have a wide monitor designed for watching videos and movies. Rather, I have a squarish monitor designed for documents, so horizontal space is at a premium, and there is more horizontal space being wasted in 115 than there was in 102 -- vertical space too.

The clone, Betterbird, lets the header be collapsed by dragging mouse, so it 'should' be available in Thunderbird. I don't know if that request has been posted.

I like the compactheaders addon

Since I started this threat (with a bit of an attitude, frankly), I should post an update. I discovered that several of the new bars (or whatever they are called) which were gobbling up space could be disabled. I also contacted the developer of the Compact Headers extension, and he updated the extension to make it work better -- that had the effect of reducing space in the mail headers area in the middle of the program. In addition, I have "density" sex to maximum, which helps. Consequently, I decided not to downgrade to version 102. It still angers me, however, that the developers came up with with an upgrade with such a clunky interface.

I'd like to make a point, and that is that screen space is a precious thing. On the newer monitors, which are wide, the vertical space is actually less than it was on the older, squarish monitors. However, because I work mostly on documents and watch very little media on my computer, I have one of those squarish monitors, which means that horizontal space is at a premium. The developers need to design interfaces that are designed to maximize space for the actual data in the program.

So this is my solution: (1) delete bars that aren't needed, (2) get the Compact Headers extension, and (3) keep Density set to maximum.

David, tell me about "Betterbird" -- what is it exactly?

It is a "soft" fork of Thunderbird maintained by Thunderbird's first employee post Mozilla. I am a financial contributor to the project because I see it delivering what the Mzla team are not.

Get it here https://www.betterbird.eu/

At this point is is 100% profile compatible with Thunderbird and I run it on the same profile I use in Thunderbird.

So, if I send and receive emails via Betterbird, but then decide to switch back to Thunderbird, the messages will be there, right?

Also, is the interface better or worse than Thunderbird, in your opinion?

Thanks.

Its main difference out of the box is that the menu bar is on top, and threading is set to UNthreading. It offers a few tweaks of its own that you can read about on its website. CSS changes on one will work on the other. Like Matt, I also support the project, primarily because I hope to see a melding of the two at some future date. Despite that, supporting Thunderbird is primary, as Thunderbird's development and evolving features are the driving force and Betterbird builds on that. For the future, it is on Thunderbird where donations need to focus. On your question, the interface is identical.