I can no longer save any changes in the settings area, no matter what page Sales, CRM, General Settings, ...
I get the red popup with
The following fields are invalid:
Languages
On those setting pages there are no (visible) fields about Languages.
I have not changed anything that has to do with languages, the only thing i can think of is that the docker container has been upgraded to a more recent version. I currently run Odoo 12.0-20190816 (Community Edition).
Anyone has an idea how to solve this ?