OK, new version of LIbreOffice works fine with V11.1 of Big Sur. Not noticing any differences, though, from V7.0.3.
Also, V78.6 of Thunderbird was released earlier today:
https://www.thunderbird.net/en-US/I downloaded and installed it, and the minor "annoyance", at least when I use it with Big Sur, is gone.
Note, though, that there is no mention of specific Big Sur compatibility. For Thunderbird, there is a beta version, V84.0.2, that is in development, and has shown promise of being compatible. But I am not experiencing any issues.
