Thunderbird email problem

Gmail keeps returning T-bird messages. Tried two Gmail locations (one mine,
the other my sister) so not Gmail setting. Once put it in Gmail Spam folder
instead of returning it. Can't find an email support address for Mozilla.
One clue from Mozilla says T-bird version should be 38 or newer to work
with Gmail. My T-bird says it is 2 and when I check for updates says none
available. I just DLed and started using this one less than a year ago. Up
till a week or two ago it worked fine with Gmail.

I guess I'll have to replace T-bird with another enmail ap. Not Gmail or
Eudora.

Any suggestions to make it work or what to replace it with?

TIA



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I love a good meal! That's why I don't cook.