So does this break seemless nostr client compatibility?
Devs, be aware that Amethyst is now encrypting all NIP-51 lists with NIP-44 instead of NIP-04. This will inevitably break some stuff, but it is about time. https://github.com/nostr-protocol/nips/pull/2034#event-19325790870
Discussion
Yes. NIP-04 clients will not be able to see the private parts of these lists.