Comment 22 for bug 2034664

Also enabling proposed gnome-shell-extension-ubuntu-dock is NOT upgraded.
corrado@corrado-n6-mantic:~$ apt policy gnome-shell-extension-ubuntu-dock
gnome-shell-extension-ubuntu-dock:
  Installed: 87ubuntu1
  Candidate: 87ubuntu1
  Version table:
     87ubuntu2 100
        100 http://archive.ubuntu.com/ubuntu mantic-proposed/main amd64 Packages
        100 http://archive.ubuntu.com/ubuntu mantic-proposed/main i386 Packages
 *** 87ubuntu1 500
        500 http://archive.ubuntu.com/ubuntu mantic/main amd64 Packages
        500 http://archive.ubuntu.com/ubuntu mantic/main i386 Packages
        100 /var/lib/dpkg/status
corrado@corrado-n6-mantic:~$ sudo apt upgrade
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Calculating upgrade... Done
The following packages have been kept back:
  firmware-sof-signed
0 upgraded, 0 newly installed, 0 to remove and 1 not upgraded.
corrado@corrado-n6-mantic:~$