Signal will let you sync old messages when linking new devices

Signal is rolling out an end-to-end encrypted message history sync for newly linked devices (e.g., desktops and iPads), creating an encrypted archive on the primary device and transferring it via a direct, server-relayed channel using a QR-verified, one-time 256-bit AES key; the archive covers messages, stickers, calls, groups, reactions, and receipts, while media is relayed as encrypted server links limited to the last 45 days, with plans to extend retention and enable future restoration, and users can join the beta to test the feature.