KDE neon's FAQ page has this:
KDE neon does continuous deployment of the latest KDE software which
means there are nearly always new versions of our software to update
to. We recommend using Plasma Discover's updater which appears in your
If you prefer to use the command line you can use the pkcon command:
This will install all new packages and uses the same PackageKit code
as Plasma Discover. Some uses of apt do not install new packages which
makes it less suitable for KDE neon.
It seems, based on the last sentence in the quoted material, the KDE neon developers believe that
apt upgrade isn't suitable. To ensure users don't go that route, the KDE neon developers have somehow disabled
apt upgrade. As suggested by the terminal output, you need to use
apt full-upgrade or
apt-get dist-upgrade if you don't want to use
pkcon or Discover.
This is still the case after today's update to Plasma 5.16.
If the use of
apt upgrade instead of
apt full-upgrade is important to you, you can
- file a bug which will probably be closed with a WONTFIX or
- use another distribution such as Kubuntu 19.04 (with the Kubuntu backports ppa) which, more or less, keeps pace with KDE neon's Plasma updates but allows
I, personally, have no issue with using