Hello,

I’m a KDE neon user, but my parents are stil on Kubuntu. I want to change the alias they use to have a Kubuntu up to date. Should they use pkcon too, or the command doesn't existe on Kubuntu? (I don't have yet access to their PC)

Thanks.

Pkcon is simply the command line for the Packagekit system, which is used by Discover, Gnome Software, and other tools. Any system that has Discover already has the pkcon command. Note that Discover/pkcon/Gnome Software on Ubuntu based systems (including KDE Neon) are actually using the system's native package management tools (apt/dpkg) to do the actual work.

tl;dr
pkcon is already there and can be used if desired.

imo it make no difference it they use apt, or packagekit (via Discover or Pkcon). Also imo if pkcon is being used, might as well just use Discover.
If using the command line, imo apt is slightly more useful as the output on screen is cleaner and more useful when errors occur. Other wise, since it is using apt under the hood, why not just use that, if using the terminal?

But ultimately you can safely use whichever tool you prefer