When attempting to use the Discourse API, cmdntd encountered an issue with two IDs being displayed: the ID of the private message and a larger ID (seemingly for editing the private message). After investigating, pfaffman clarified that the smaller ID is the topic.id (used for changing the title) and the larger ID is the post.id (used for changing the raw content). To update message details, the post.id must be used, while the topic.id is used for updating the title. This can be observed in the topic’s JSON data, as demonstrated by pfaffman.
The title is part of the topic, raw is part of the post. If you look closely in the post, you’ll see a topic_id field that contains the number that you’re calling the private message ID.