https://jumble.social/ has launched DM support, implemented as NIP-17 DMs on top of NIP-4e (https://github.com/nostr-protocol/nips/blob/per-device-keys/4e.md).

At the moment only coop supports this protocol, so communication is currently only possible between Jumble and coop users.

Benefits of NIP-4e (decoupling the encryption key from the user's identity key):

- The encryption key can be rotated regularly, reducing the risk that a compromised or lost key exposes historical messages
- Encryption and decryption no longer require the user's identity key. Previously, using DMs with a bunker remote signer resulted in a poor user experience