Where is thunderbird_portable_3.1.7

I've chosen at least for now to remain with the Thunderbird Portable 3.x series.
I keep getting notices to upgrade to 3.17 (I'm currently at 3.16)
Googling and searching this site located:
https://portableapps.com/news/2010-12-09_-_thunderbird_portable_3.1.7 but the download link on it points to the main download and hence to Thunderbird 9.

Does anyone know where I can locate 3.17 which apparently was a some past time available?

[Edit add] I suspect the above was an erroneous post since on
https://www.mozilla.org/en-US/thunderbird/3.1.17/releasenotes/?uri=/thun...
I see v.3.1.17, released December 20th, 2011

I guess I'll have to just keep clicking [Later] every day [/Edit add]