Hello,
Thank you for your question.
Indeed, when doing a featuresearch, the "detail" returns everything in lowercase. This is standard and cannot be changed
In order to get your wanted return, you have 3 possibilities:
1. Add yourself the uppercase: Take the "detail" return and internally add a parameter that ensures the first letter after the ZIP code to be in upper-case.
2. Second query: The first return must be supplemented with a second query to the feature endpoint using the resulted feature id. The wanted result would be visible in the "langtext" parameter.
3. Download the data: This alternative depends on the user case - You have the possibility to download all the data from
here in different formats. They are updated every month and could therefore be easily replaced automatically updated internally.
For forther information, don't hesitate to visit our
TechDocs.
We hope this could be helpful.
Best regards,
Help Desk federal geoportal