I have tried to change the default email client to thunderbird. I did so via systemsetting --> applications --> default applications. I put in there "thunderbird" as the default email client. Unfortunately the default seems not to have changed because every application which uses mailto is poping up kmail client and not thunderbird.
Any suggestions how to solve this? Is there a commanline way to change the default email client?
Best Benjamin.
I am working on ubuntu 18.04 with Kde Plasma 5.12.5
Search for System Settings in the menu. Open. Go to the Applications submenu and under Default Applications select Email Client. Click the radio button for 'use a different email client' and enter thunderbird %u. Then Apply.
If that doesn't work try right clicking at the top of Thunderbird to show the menu bar. Go to the Edit menu, select Preferences and then Advanced on the window that pops up. Under the General tab there is a System integration setting with an option to check that Thunderbird is the default email client.