As this is a release, can i post a new thread in the “release announcements” or can i just update the post i created a while back?

Based on the rules of Release Announcements, there’s no specific line on what counts as a “new release”. However, if the only difference is supporting a new platform, I think it’s better if you update the previous thread.

If I update, will it bump the post back to the top?

Yes, it should bump it on top, so it will be similar to making a new post.

Is this even allowed at all?

Assuming you are updating a thread genuinely because there’s something new to add, and it’s something that doesn’t happen too often, it should be allowed.

If i create one on via the game dashboard will it appear in the Devlog section of the forum or shoud I create a new thread directly in the forum section?

I believe the Devlog section is updated from individual project’s Devlogs, and they are not connected to the community forum ones. I’m not very familiar to how they are connected.

Hope that helps :)