Follow-Up: Sadly no longer compatible.
Looks like FB changed it’s export format:
[{"timestamp": 1566833332,"attachments": [],"data": [{"post": ""},{"update_timestamp": 1566833332}],"title": ""}]
This is not what Ditchpost expects.
The posts file is also no longer posts/your_posts.json but posts/your_posts_01.json