My Linux Mint 18 (64bit) upgraded my Thunderbird to version 91.5.0. That version is a mess. I am trying to ask a question and Mozilla wants to send replies to my primary email. Unfortunately due to the Thunderbird upgrade I can no longer pop my emails to that address nor send anything.

I have a gmail account that works but how do I change my primary email address since Mozilla keeps sending me a code to an address that Thunderbird won't let me get mail at?