I have been reading up on the releases to see what modifications have been incorporated. This may be of interest to you.

Release notes for version 60.0 https://www.thunderbird.net/en-US/thunderbird/60.0/releasenotes/ Changed: "Edit As New Message" will now use the account's default compose format, either HTML or plain text ignoring the format of the message. Plain text messages will be converted to HTML and vice versa. Then using the modifier, the format choice will be reverted.

The plain text to HTML conversion has been improved where such a conversion is necessary for "Edit As New Message" or when the shift modifier is used for "Edit Draft" or "New Message from Template".

Current version is 60.2.1 https://www.thunderbird.net/en-US/thunderbird/all/

I am running 52.9.1. I have auto update turned on. Shouldn't I have been upgraded to v60.2.0 by now?

You mention you are using a MAC, but I'm not sure what version etc to ensure updating is possible. The info below is copied from the release data. If you view Help > About Thunderbird, does it offer the option to update?

Thunderbird version 60.2.1 provides an automatic update from Thunderbird version 52. Note that Thunderbird version 60.1.0 and 60.2.0 were skipped. If you have installed Lightning, Thunderbird's Calendar add-on, it will automatically be updated to match the new version of Thunderbird. Refer to this Calendar troubleshooting article in case of problems.

System Requirements: • Window: Windows 7, Windows Server 2008 R2 or later • Mac: Mac OS X 10.9 or later • Linux: GTK+ 3.4 or higher. Specific details below: Mac Operating Systems

• Mac OS X 10.9
• Mac OS X 10.10
• Mac OS X 10.11
• Mac OS X 10.12
• Mac OS X 10.13

Recommended Hardware

• Macintosh computer with an Intel x86 processor
• 512 MB RAM
• 200 MB hard drive space

Thunderbird says it is up to date with v52.9. See the attached screenshot.

Please advise. I'd love to get upgraded to the new version that fixes this issue.

I normally recommend this page when a user wants to force an upgrade:

https://www.thunderbird.net/en-US/thunderbird/all/

I just downloaded the Mac version from there and it gave me TB60.2.1. Be aware that many of your add-ons may stop working with this version.

All current and past versions (and even some un-released beta versions) can be found here:

https://ftp.mozilla.org/pub/thunderbird/releases/

This is handy if you need to revert an upgrade.

Good news - the problem has been fixed in v60.2. The html message now comes up in plain text. Very nice!

Thanks very much!

And I was wrong. I missed that change.