Two new KDE applications (QML based for both) have been added to the repositories.
First is Skanpage. It will become part of the monthly KDE apps/gear releases this year, and will replace Kooka.
Kooka is still available, since Kalendar is not as feature rich yet, but Kooka is not an option to keep much longer. It has always been build from a git checkout since it has never had a Qt5 based release, in the years it has been in repos, it has been dormant most of the time. Skanpage is very active developed.

Next added is Kalendar, a Kirigami-based calendar application that uses Akonadi. It lets you add, edit and delete events from local and remote accounts of your choice, while keeping changes synchronised across your Plasma desktop or phone.
It has a few more features than korganizer and will be part of the kdepim suite this year, thus it is added already.