Thank you AndrĂ¡s, that fixed the 24hr time setting. We have still issues with date format. For example todays date displays 12-04-2017 but our requirements are 12.4.2017. (j.n.Y)
This might be related. If I check the “Single geography mode” in Events -> Settings -> Community it still shows me the country, timezone and state options in the new event form.