Mailchimp API: Unable to trigger Events with umlauts in properties

I’m using the Mailchimp Events API to trigger events on the members in our Audience list. In general the API works as expected: When I send an event, I can see the event's name and properties in the member’s activity.

However, if any of the properties in the Event contain German umlauts, it doesn’t work. It records the event on the member but without the properties.

For example: When the event is triggered as follows:

curl --location --request POST 'https://us4.api.mailchimp.com/3.0/lists/1234/members/12343124/events' \
--header 'Content-Type: application/json; charset=utf-8' \
--header 'Authorization: Basic TED' \
--data-raw '{
    "name": "test-event",
    "properties": {
        "link": "Münich"
    }
}'

The event is records under the member's activity but without the properties.

Hope someone could help me out with this.

Thanks in advance.

Solution

Turns out Mailchimp Event API endpoints don't support it.

This was the response from Mailchimp API's support team:

Currently, using special characters in data passed over in relation to the Events endpoint is not supported. Our developers are aware and we're tracking feedback as a fix is in the works. I don't have a current ETA for that, unfortunately. The best option at this time is the avoid using special characters whenever possible, and please send any specific occurrences of this that you see our way so we can add them to our tracking.