Hey Jeremy, 100.7 officially supports Catalina and Mojave - https://developers.arcgis.com/qt/latest/qml/guide/system-requirements-100-7.htm#ESRI_SECTION1_BDCD14...
We are in the process of finishing our 100.10 release, which will be our first release to officially support Big Sur. Our general cadence is that we try to support the latest 2 releases of macOS with each new release. We don't go back and re-certify older releases on newer operating systems.
Is it possible to coordinate the upgrade with the 100.10 release in January? Otherwise, if you must upgrade now, it might be worth trying to upgrade a single test machine first to do some testing to see if you encounter any issues before pushing it out to everyone.
