Blockstream has broadcast what are, to the best of our knowledge, the first transactions on a production #Bitcoin sidechain signed with a post-quantum signature scheme. Real transactions securing real value on #Liquid mainnet. This works not only with bitcoin, but also with any asset issued on Liquid.

https://blog.blockstream.com/blockstream-research-demonstrates-quantum-resistant-transaction-signing-on-liquid-using-simplicity-smart-contracts/