Hello, all! Some of you are aware that we’ve been working on a pretty cool device-independent backup format, and now we’re looking to test our first use-case: syncing your message history with a newly-linked device! You heard that right – your newly-linked devices will finally have all of your message history 🎉 I think this is something we’ve all wanted for a while, so it’s really cool to finally build it. But building something like this is very tricky, and testing it tends to uncover lot...
The only media that syncs is media that was sent/received in the last 45 days, because that’s how long encrypted media lives on Signal’s servers in order to match the current maximum timeframe for queued messages for offline devices. Media older that that will not be available.
So that begs the question, if text messages don’t live longer, why are they able to sync from older than 45 days? I’m guessing its because they are sent p2p? But in that case, why is media then not also sent p2p? Is it because of amount of data/transfer speeds?
It’s probably not sent P2P. It’s probably sent via their server as relay. If they pushed media from the sender device to the receiver, they’d have to reupload all that which could be a lot of traffic which costs, so they just relay the media they already have and only reupload the text. That’s my hypothesis.
There is also this quote, which is weird:
So that begs the question, if text messages don’t live longer, why are they able to sync from older than 45 days? I’m guessing its because they are sent p2p? But in that case, why is media then not also sent p2p? Is it because of amount of data/transfer speeds?
It’s probably not sent P2P. It’s probably sent via their server as relay. If they pushed media from the sender device to the receiver, they’d have to reupload all that which could be a lot of traffic which costs, so they just relay the media they already have and only reupload the text. That’s my hypothesis.