I don´t want to ask the same question here again. But to understand the origin of my question this could be helpful (https://stackoverflow.com/questions/26054246/sharepoint-2013-fetch-only-last-approved-version-through-rest-api).
Now I found out that:
It is not possible to reflect the approval status in an item to make it visible in a json response from rest api call. This is because you cannot use field approval status in a calculated field and the field itself is not populated through rest response.
I tried to set a custom field item_approval_status through a workflow but this is messing up workflows because this workflow is making a change to the item which causes other necessary workflows to start (could end up in infinite loop..)
So what I want to achieve is:
Favorite:
To make 1 rest call and get only the last approved version of an item for ALL users (even those who are allowed to see drafts)!
Workaround:
To reflect the current approval status in each item to (at least) provide a label to each item that is not approved. So approvers and the author can see that this is the draft state.