Re: gnome-shell-3.20.2-3 ??
Where did you find a reference to version 3.20.2-3.fc24? The latest build in koji is the one that is in the repos, 3.20.2-1.fc24.
As far as I can tell, if there is a newer build, it was done by someone else.
According to Gnome, there was no 3.20.2-3 patch release. They went from 3.20.2 to 3.21.1.
I did find a reference to a patch in Arch, but that isn't Fedora, and the Fedora packagers may or may not pick up that patch.