I recently upgraded my work workstation from RHEL6 to Ubuntu 20.04, so was able to move from mutt 1.5.20 to 1.13.2 ... and now I have threading!
I know it's still far behind the latest versions, but it's very exciting, and I'm very thankful. Andy -- Andrew D. Arenson (he/him) H 317.964.0493 arenson (at) spatzel.net C 317.679.4669