I remember that Skype, before it was bought and ruined by Microsoft, had P2P chat history sync that worked the following way: once two of your devices were online at the same time, they synchronized chat history among the two running instances flawlessly. It was super reliable and predictable.
I am sure that Signal could implement the same peer-to-peer sync scheme with full end-to-end encryption without any secrecy compromises.
I am sure that Signal could implement the same peer-to-peer sync scheme with full end-to-end encryption without any secrecy compromises.