I was following the instructions in this page for installing KDE on PureOS: https://tracker.pureos.net/w/pureos/tips/install_kde/ and I got everything installed and working properly, but the KMail and KOrganizer. Both sofware have unmet dependencies:
sudo apt install kmail
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
kmail : Depends: akonadi-server (>= 4:16.04) but it is not going to be installed
Depends: kdepim-runtime but it is not going to be installed
Depends: libkf5akonadisearch-plugins but it is not going to be installed
Depends: kdepimlibs-data (>= 4:15.12~) but it is not installable
Depends: kf5-kdepimlibs-kio-plugins but it is not installable
Depends: libkf5akonadiagentbase5 (>= 15.07.90) but it is not going to be installed
Depends: libkf5akonadicalendar5 (>= 15.07.90) but it is not installable
Depends: libkf5akonadicontact5 (>= 15.07.90) but it is not going to be installed
Depends: libkf5akonadicore5 (>= 4:16.04.0) but it is not installable
Depends: libkf5akonadimime5 (>= 4:15.12.0) but it is not going to be installed
Depends: libkf5akonadisearchdebug5 but it is not going to be installed
Depends: libkf5akonadiwidgets5 (>= 4:15.12.0) but it is not installable
Depends: libkf5alarmcalendar5 but it is not going to be installed
Depends: libkf5calendarcore5 (>= 15.07.90) but it is not going to be installed
Depends: libkf5calendarsupport5 (>= 4:15.12) but it is not installable
Depends: libkf5calendarutils5 but it is not going to be installed
Depends: libkf5contacts5 (>= 15.12.0) but it is not going to be installed
Depends: libkf5followupreminder5 (>= 4:16.04.0) but it is not going to be installed
Depends: libkf5gravatar5 (>= 4:15.12) but it is not installable
Depends: libkf5identitymanagement5 (>= 16.04.0) but it is not going to be installed
Depends: libkf5incidenceeditor-bin but it is not going to be installed
Depends: libkf5incidenceeditor5 (>= 16.04) but it is not installable
Depends: libkf5kmanagesieve5 but it is not going to be installed
Depends: libkf5kontactinterface5 but it is not going to be installed
Depends: libkf5ksieveui5 but it is not going to be installed
Depends: libkf5libkdepim-plugins but it is not going to be installed
Depends: libkf5libkdepim5 (>= 16.04) but it is not going to be installed
Depends: libkf5libkleo5 (>= 4:15.12) but it is not going to be installed
Depends: libkf5mailcommon-plugins but it is not going to be installed
Depends: libkf5mailcommon5 (>= 4:16.04.2) but it is not installable
Depends: libkf5mailimporter5 (>= 4:15.12) but it is not going to be installed
Depends: libkf5mailtransport5 but it is not going to be installed
Depends: libkf5messagecomposer5 (>= 4:16.04.0) but it is not going to be installed
Depends: libkf5messagecore5 (>= 4:15.12) but it is not going to be installed
Depends: libkf5messagelist5 (>= 4:15.12) but it is not going to be installed
Depends: libkf5messageviewer5 (>= 4:16.04.0) but it is not going to be installed
Depends: libkf5mime5 (>= 15.12.0) but it is not installable
Depends: libkf5pimcommon-plugins but it is not going to be installed
Depends: libkf5pimcommon5 (>= 4:16.04) but it is not installable
Depends: libkf5pimtextedit5 (>= 15.12.0) but it is not installable
Depends: libkf5sendlater5 (>= 4:16.04.0) but it is not going to be installed
Depends: libkf5templateparser5 (>= 4:15.12) but it is not going to be installed
Recommends: accountwizard but it is not going to be installed
Recommends: gnupg2 but it is not going to be installed
Recommends: kdepim-addons but it is not going to be installed
Recommends: kdepim-doc but it is not going to be installed
Recommends: kdepim-themeeditors but it is not going to be installed
Recommends: ktnef but it is not going to be installed
E: Unable to correct problems, you have held broken packages.