Hi there,
i just installed a fresh 8.170 and restored a backup in which the Webadmin Language was set to german.
I clicked on the settings and tried to switch from english to german and klicked on apply, the green "ok" massage didn't appear .. i logged out and back in again and the language was not set to german on the webinterface, but the dropdownbox was set to german.
After i set it back to english and again back to german the website switched to german.
Robert