Since the update to the 17.04 Version, Addressbook and Korganizer are not synced anymore. The 17.04 Update installed a new package "kdav" (17.04..). Since that time it is still possible to set up a new calendar in "DAV- Groupware Resources". After adding required user information and collecting the resources, Events are not displayed in Korganizer, and Contacts are not displayed in Kaddressbook. It you have already setup your account before the upgrade, everything is visible but it is not syncing anymore with a webdav server. I am collecting email, Contacts and Events from my provider mailbox.org. Collecting Emails is not affected. Bernd
KDE Frameworks 5 has been updated to 5.34.0 - That solves the problem
I could isolate the issue. It seems to be a problem with PCLinuxOS. Setting up a new webdav accound for korganizer and kaddressbook works flawlessly, but the existing dates fetched from the server are not displayed at all !! Any new contacts or dates made with korganizer are displayed and synchronized with the server properly.