Hi so I've been lurking occasionally and I see the status change after an interview is a topic so I want to give my own 2 cents. I interviewed on Dec 8th and my status changed to received/under review as well since then with no changes. I did send a LOI (basically reiterating intent and providing updates) 2 weeks ago and I got a response back stating my app is still under periodic review and if there are any updates they need, they will let me know. So! I assume that means those in the same boat are also still under periodic review. There's a chance.
However, I'm not sure that it means acceptance? I don't know why they've chosen to still keep us under tabs (even tho some of y'all interviewed pre-dec), and I haven't seen anyone in this thread mention rejections or waitlist decisions yet. But I personally don't think that this status change means we're 100% getting accepted. All I can say for now is if you do have questions about the status of your app, it wouldn't hurt to send an email. As far as LOI's, only send one at most and don't press them any further. I don't think I ruined my chances in sending one but based on their reply, I definitely do not think they're receptive to the further updates that are usually recommended regarding LOI's.