Preparing to unpack .../plasma-desktop_4%3a5.8.3-0ubuntu1~ubuntu16.04~ppa1_amd64.deb ...
Unpacking plasma-desktop (4:5.8.3-0ubuntu1~ubuntu16.04~ppa1) over (4:5.5.5-0ubuntu1) ...
dpkg: error processing archive /var/cache/apt/archives/plasma-desktop_4%3a5.8.3-0ubuntu1~ubuntu16.04~ppa1_amd64.deb (--unpack):
 trying to overwrite '/usr/lib/x86_64-linux-gnu/qt5/qml/org/kde/activities/settings/libkactivitiessettingsplugin.so', which is also in package qml-module-org-kde-activities:amd64 5.18.0-0ubuntu1
dpkg-deb: error: subprocess paste was killed by signal (Broken pipe)

and

Errors were encountered while processing:
 /var/cache/apt/archives/kio-extras_4%3a16.04.3-0ubuntu1~ubuntu16.04~ppa61_amd64.deb
 /var/cache/apt/archives/kio-extras-data_4%3a16.04.3-0ubuntu1~ubuntu16.04~ppa61_all.deb
 /var/cache/apt/archives/libkf5mailcommon-plugins_4%3a16.04.3-0ubuntu1~ubuntu16.04~ppa61_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)