We start supporting them as soon as they're available! Obviously we have a lot less training data early on but we can lean on some heuristics early on until it builds up.
Unfortunately in the app we can't give you emoji that your phone doesn't support so we don't always show all the results.
Yeah we'd need to do some more work. But this is similar to stickers and GIFs: there are many fewer examples for any given sticker or GIF, which is why we do transfer-learning approaches as discussed in the article.
So there's a good chance we could get it to work! We've not focused on that possibility… yet.
Unfortunately in the app we can't give you emoji that your phone doesn't support so we don't always show all the results.