Apparently the latest version of Thunderbird in the repo's for Neon is 68.10.0. But Thunderbird is now up to 78.6.1. I figure there must be a reason why no newer version is in the repo's, but I do not see any discussion of it. Am I missing something?

Because Neon is based on the Ubuntu LTS branches, which focus on stability. 68 was the last major version of Thunderbird, & unless there's a good reason to update, Ubuntu will probably stick to that branch & so will Neon. Saying that though I do recall that on Ubuntu's last LTS they did upgrade Thunderbird to the latest major release, so you never know.

There is an open Ubuntu bug that is for backporting the Thunderbird upgrade to Ubuntu 20.04 LTS and 18.04 LTS.

https://bugs.launchpad.net/ubuntu/focal ... ug/1895643

dbergstein wrote:There is an open Ubuntu bug that is for backporting the Thunderbird upgrade to Ubuntu 20.04 LTS and 18.04 LTS.

https://bugs.launchpad.net/ubuntu/focal ... ug/1895643

They are falling farther behind as version 78.7.0 is due next week.

Thank you waynes, dbergstein, and WaltS48 for the information. Clearly it is an ubuntu issue. It seems as if it will be resolved, but as of today the most recent post at https://bugs.launchpad.net/ubuntu/focal/+source/thunderbird/+bug/1895643 , written three days ago, asks " What's still holding us back from getting the latest Thunderbird?"