The current Thunderbird version is 45.3.0

https://www.mozilla.org/thunderbird/all/

The 46, 47, 48, 49 Beta builds are more for QA testing.

The current Firefox 48.0.x Release is the last Release to work on the old Mac OSX 10.6, 10.7, 10.8 as Firefox 49.0 and newer requires OSX 10.9 or newer to run. The Firefox 45 ESR will however work and receive security updates until 45.8.0esr (unless Mozilla supports it longer) which is when Firefox 53.0 will be released. https://support.mozilla.org/en-US/kb/firefox-osx

I imagine the Thunderbird 49.0 build on Gecko 49.0 and newer versions is the same with this. I do not follow Thunderbird development to know if the devs in Thunderbird community plans to work around this change on OSX.

Thanks, James...

Interesting response, but unclear in terms of answering my question.

In particular, it would be worthwhile knowing whether there'll be security updates to the v 47 Beta I'm running -- and what Thunderbird's update timeline will likely be (for Beta versions or otherwise) in terms of my ultimately being forced to update OSX itself.

Any advice, given my reluctance to update the OS until the last feasible moment? Am I at that point now, or do I have at least some months left to go?

Perhaps someone more specifically familiar with TB can address these issues... :-)

PS: Meanwhile, BtW, I'm currently running Firefox 48.0.1.

At any one time there are three different versions of Thunderbird available – the stable release, the beta version of the following release and the alpha preview of the subsequent version called Earlybird.

current stable release is 45.3.0

security updates (if required) usually follow. eg: https://www.mozilla.org/en-US/thunderbird/45.3.0/releasenotes/ system requirements: https://www.mozilla.org/en-US/thunderbird/45.3.0/system-requirements/

Thunderbird schedule for future updates is not something an average user or helper would know. This is something the developers would know more about. If I get any info I'll post here.

Sadly, the link below was recently updated to exclude Thunderbird: https://wiki.mozilla.org/RapidRelease/Calendar now only contains info regarding 'Firefox' (great if you want to know Firefox) but no longer of any use for Thunderbird.

https://en.wikipedia.org/wiki/History_of_Mozilla_Thunderbird

Mitchell--Oakland said

In particular, it would be worthwhile knowing whether there'll be security updates to the v 47 Beta I'm running -- and what Thunderbird's update timeline will likely be (for Beta versions or otherwise) in terms of my ultimately being forced to update OSX itself. Any advice, given my reluctance to update the OS until the last feasible moment? Am I at that point now, or do I have at least some months left to go?

For Firefox the versions on the Beta channel do get updates, usually say 6 to 12 with 9 being average.

The Thunderbird Beta builds do not really get updates like Firefox does. The Tb 47.0b and 48.0b are old and if there were updates to a Beta build it would be for 49.0.

Thunderbird Releases are done in a ESR or Extended Support Release fashion every seven versions much like the Firefox ESR.

So if Thunderbird is like Firefox you will only be able to use the Thunderbird 45.X.x or the Thunderbird 48.0b which will get behind in not having security fixes like Tb 45 release will get (on OSX 10.6, 10.7, 10.8).

Mitchell--Oakland said

PS: Meanwhile, BtW, I'm currently running Firefox 48.0.1.

Firefox 48.0.x will be the last Major Release to work on OSX 10.6, 10.7, 10.8 as you will need to use Firefox 45 to have security updates for a while still. https://support.mozilla.org/en-US/kb/firefox-osx

So, James, are you suggesting that as of now (from a security standpoint) I might be better off going backward to the regular Thunderbird v 45 (if that's indeed an ESR version), rather than staying with TB 47.0.1 Beta?

Is there anyone out there familiar with Thunderbird who can answer this?

According to the TB49 beta release notes it still works with OS X 10.6. https://www.mozilla.org/en-US/thunderbird/49.0beta/system-requirements/

How exactly did you update to v49 beta?

christ1 said

According to the TB49 beta release notes it still works with OS X 10.6. https://www.mozilla.org/en-US/thunderbird/49.0beta/system-requirements/ How exactly did you update to v49 beta?

Either the page was just updated by using the page used for Tb 48.0beta or Thunderbird devs are working around this OSX requirement change in Gecko 49.0 and on. Mistakes are made sometimes on these pages.

For example for Firefox this page is correct https://www.mozilla.org/firefox/49.0beta/system-requirements/

However this Fx 48.0 page is incorrect for Mac part as Firefox 48 does indeed work on OSX 10.6, 10.7, 10.8 and should be same as 47.0 page. https://www.mozilla.org/firefox/48.0/system-requirements/ https://www.mozilla.org/firefox/47.0/system-requirements/

Either the page was just updated by using the page used for Tb 48.0beta or Thunderbird devs are working around this OSX requirement change in Gecko 49.0 and on.

The former sounds more likely to me than the latter, however, I really don't know for sure.

I suspect the "System Requirements" page was incorrect, and that TB 49 Beta does not, in fact, support OS 10.6.8, despite that page claiming it does.

I performed the update in the same fashion as always: I was prompted by TB to perform the download, a ".dmg" file which, when opened, launched the installer. That, in turn, simply overwrote the older version of the application. At that point, however I was unable to relaunch Thunderbird -- even after restarting my (iMac) computer.

Unfortunately, I didn't keep a copy of the crash log that appeared at that point.

Meanwhile, I eventually gave up, and downloaded and installed TB 47 beta, which has now been working fine.

If it would be crucial to solving the problem with v 49, I could repeat the download and installation in order to generate (and this time, save) the crash log. Nonetheless, that might not be worth the bother if it's established that, in fact, v 49 isn't designed to work with OS 10.6.8 in the first place. I suspect someone on the development team already knows the answer to that, without having to pore over a crash log. :-)

Mitchell--Oakland said

I suspect the "System Requirements" page was incorrect, and that TB 49 Beta does not, in fact, support OS 10.6.8, despite that page claiming it does.

Correct

I performed the update in the same fashion as always: I was prompted by TB to perform the download, a ".dmg" file which, when opened, launched the installer. That, in turn, simply overwrote the older version of the application. At that point, however I was unable to relaunch Thunderbird -- even after restarting my (iMac) computer.

As has been suggested in this thread Beta software is not release quality and is mean for testing. You have tested it and found it (or the information) wanting. Thank you for your contribution to the making of Thunderbird.

Unfortunately, I didn't keep a copy of the crash log that appeared at that point.

Not necessary.

Meanwhile, I eventually gave up, and downloaded and installed TB 47 beta, which has now been working fine.

Thunderbird and Firefox at this point in time and for the next couple of versions at least share the same internal Geko rendering engine. Given that all of the development on that engine is done by Mozilla. For things as fundamental as system requirement the Firefox information should be considered canonical and anything else an error of some sort.

If it would be crucial to solving the problem with v 49, I could repeat the download and installation in order to generate (and this time, save) the crash log. Nonetheless, that might not be worth the bother if it's established that, in fact, v 49 isn't designed to work with OS 10.6.8 in the first place. I suspect someone on the development team already knows the answer to that, without having to pore over a crash log. :-)

I think that is an excellent analysis of the state of things. Although I think this might be the first the Thunderbird development folk have really heard of dropping those OSX versions. We have to observer the change, they do not tell us.

Thanks, Matt!

That leaves one remaining question: Would I be better off now (from a security standpoint) going backward to the regular Thunderbird v 45 (if that's indeed an ESR version), rather than staying with TB 47.0.1 Beta?

If I've read these posts correctly, that would keep me fully viable until sometime next year -- by which time I'll be able to update OS X (ironing out all the inevitable problems that occur with a major OS update), and resign myself to paying for new versions of MS Office, Toast, and (Ugh!) Adobe Creative Cloud (along with whatever else I discover no longer works with the new OS). ;-)

If all of that is true, how can I be sure the version I'm downloading is indeed an ESR version -- and while I'm at it, that I'm running the right version of Firefox, too? Could you post links?

As far as the current release version of Thunderbird goes. getthunderbird.com will always redirect to the latest release version.

The getfirefox.com does the same for firefox,

Last evening when Christ1 emailed about this issue, I was initially concerned that the next release of Thunderbird in the 45.X would be affected. That is not the case as Thunderbird release is built on the ESR version of Geko. Reading the Firefox bugs makes it clear that the ESR branch on which Thunderbird is built will update each 6 weeks for stability and security until around the time Thunderbird 52 is released. The last 45.X will probably appear a week after the 52 release occurs. So you should be good to go for a while yet.

For those using powerPC based OSX, there is tenfourbird which is a community build of Thunderbird that runs on osx10.4. Looks like you might be the meat in the sandwich at this point in time, but keep an eye out. Just as dropping support for powerPC spawned tebfourbird, these older OSX versions could well spawn a community build in the same manner for earlier OSX versions. Reading the Firefox Bug on the topic, it appeared not to be a technical issue that saw support dropped. Just that the versions were unsupported by Apple.