After a few tests and improvements I have made, Sparky-APTus-Upgrade works as I wish to.
The package has been upgraded up to version 0.1.7 and provides the recommended tool for upgrading Sparky installation. The tool will be pre-installed in the December’s iso images.

0.1.7 changelog:
– added re-refreshing package list after finishing/breaking the upgrading process
– if the process will be broken due to lost connection or the connection hasn’t been done – you will be posted about that
– the main upgrading process is showed in a terminal emulator window, instead of a GUI window. Some of the updates/new packages need to be accepted by you
– Terminator has to be installed as a dependency, but it doesn’t make any change with your Terminator’s config file (if you have it). The package ‘sparky-terminator-config’ features its own config file which is located in a separated directory. Sparky’s Terminator configuration removes the window borders, close buttons and hide from taskbar – it protects against shooting down the window during the upgrading process

If you’d like to install it, rut the commands as root:
apt-get update
apt-get install sparky-aptus-upgrade

The app will be available in the Menu-> System-> System Upgrade

Sparky APTus Upgrade

After installing Terminator, the default terminal emulator has been changed for Terminator.
To get back previous terminal settings, run as root:
update-alternatives --config x-terminal-emulator
and choose you favorite terminal emulator.