Your second picture shows that you are in fact composing in HTML format, otherwise you wouldn't see the Formatting Toolbar or the Format and Insert menu items. Hold Shift when you click the Write button to see the plain text message composer.

No. Before, I could see at the bottom of the drop-down menu under Format, the option to format in HTML. Now, since the last update, it is no longer there. I tested this out before posting. Trying to send myself an HTML coded email and that's what I received - the HTML coding. I've been using Thunderbird for years with no problems until this new release.

The kind of 'format' you mean is not under the Format menu; it's under Options/Delivery Format. If you send an HTML message as in your test, it will appear as it does in your picture if View/Message Body As is set to Plain Text.

I've been using Thunderbird for years, coding in HTML at will in the manner as I described. Additionally, I could view and correct the HTML if and when necessary in a vertical panel on the right-hand side of the page. Now, I see no way to do even that. What you are saying may very well be true under the current release of Thunderbird, but it no longer functions the way it did for me in 52.9.1

Perhaps you are correct in that the 'option' to code in HTML is under 'Options' rather than under 'Format', but since that option has disappeared for me I cannot verify that. It was at the bottom of the drop-down menu of one of the two, Format or Options. I'm not making this up.

In short, I was able to code in HTML/Rich Text, etc, and send out emails formatted however I wished and have it received and viewable as it would be as if it were on a web page, displaying images and other formatting and now I cannot. At least, I cannot see how to do it as I could before.

The EditHtml add-on includes the menu item you describe under the Format menu. To enable or install it in TB 60, first open Tools/Options/Advanced/General/Config. editor and double-click the preference extensions.strictCompatibility to false, OK to close Options.

You can also consider ThunderHTMLedit as an alternate.

Thanks. I've been using it for so many years I had completely forgotten that it was an Add-on. I see Edit Html again under Format where I had remembered seeing it. The new release must have disabled it. I've now opted out of automatic updates without my go-ahead.

Now I can stop pulling the rest of my hair out.