You need to be on version 128 to get export capabilities.

Wayne Mery, thank you. Now on a crayola level, how do i upgrade from 115.18.0 to 128?

wayne Mery, i have downloaded the file for thunderbird 139.0.2.......i do not know how to install it???????

See https://support.mozilla.org/en-US/kb/installing-thunderbird-linux and https://www.google.com/search?q=how+to+install+thunderbird+linux+%22tar.xz%22&oq=how+to+install+thunderbird+linux+%22tar.xz%22&gs_lcrp=EgZjaHJvbWUyBggAEEUYOdIBCTI3NTIxajBqN6gCALACAA&sourceid=chrome&ie=UTF-8

Wayne Mery has tried to help sort of. I now have flatpak on my terminal. I need to install thunderbird 139 to my desktop with 115 already on it. Wayne Mery sent me this: https://www.google.com/search?q=how+to+install+thunderbird+linux+%22tar.xz%22&oq=how+to+install+thunderbird+linux+%22tar.xz%22&gs_lcrp=EgZjaHJvbWUyBggAEEUYOdIBCTI3NTIxajBqN6gCALACAA&sourceid=chrome&ie=UTF-8 and it is not much help!!! Also, my question says there are 4 replies! How do i see the other 3 replies, maybe my answer is there? I had thought my 115.18.0 was going to automatically update. Obviously, it hasn't. Thank you...b³

reading more, i now have flatpak and flathub on my terminal. I am also cautioned that thunderbird 128 will only coexist with my TB 115. is there a SIMPLE way to have my 115 data, old emails etc, contacts etc., address books etc., all move easily from 115 to 128 without skipping a beat? Thank you....b³