[_odey]

Signal has end-to-end encryption and you are able to see the conversation on other devices from the point you link your devices.

What it does not have is the ability to send your conversation history to your linked devices (which I find a bit odd, if you can trust a device with your present/future conversations, you should be able to trust it with your past, or at least be able to opt in in trusting it with sending over your past conversations). I hope they will provide this in the future.