Some updates:

We've finally sorted out the Apple developer account. We expect to release the iOS version of Keychat within a week or two, and possibly a macOS version as well (although the UI isn’t fully optimized for large screens yet).

We're currently revising our MLS group implementation. We've studied the codebases of NIP-104 and White Noise in depth and learned some useful design ideas—such as encrypting MLS messages using NIP-44 and hiding the `group_ID`. We’ve also been posting comments and discussing better mechanisms, like more efficient ways to update the MLS group’s receiving addresses. Ultimately, we hope different MLS clients will be able to interoperate.