I got a Xenial ISO and run it in a virtual machine.
Enabled proposed and now upgrading update-manager forces the installation of a newer ubuntu-advantage-tools:
---> $ sudo apt install update-manager --verbose-versions ... The following packages will be upgraded: python3-update-manager (1:16.04.17 => 1:16.04.21) ubuntu-advantage-tools (10ubuntu0.16.04.1 => 31.2.2~16.04) update-manager (1:16.04.17 => 1:16.04.21) update-manager-core (1:16.04.17 => 1:16.04.21) <---
I confirm then that launching and finishing update-manager without internet connection produces no error any more.
I got a Xenial ISO and run it in a virtual machine.
Enabled proposed and now upgrading update-manager forces the installation of a newer ubuntu- advantage- tools:
---> update- manager (1:16.04.17 => 1:16.04.21) advantage- tools (10ubuntu0.16.04.1 => 31.2.2~16.04) manager- core (1:16.04.17 => 1:16.04.21)
$ sudo apt install update-manager --verbose-versions
...
The following packages will be upgraded:
python3-
ubuntu-
update-manager (1:16.04.17 => 1:16.04.21)
update-
<---
I confirm then that launching and finishing update-manager without internet connection produces no error any more.