Signal users switching between Android and iPhone devices can now transfer their message histories, following a series of backup updates completed in version 8.30 for iOS. The cross-platform capability allows backups to move easily across Android, iOS, Linux, macOS, and Windows. These changes expand upon Signal Secure Backups, an optional end-to-end encrypted backup service that launched in September 2025.
Cross-Platform Architecture and On-Device Storage Changes
The messaging platform rebuilt its Android client to use a unified backup format shared with Signal Desktop and Signal for iOS. This update marks the first time desktop and iOS applications can generate local, on-device backups. Previous Android iterations stored all data inside a single, cumbersome archive that bloated daily snapshots. Media files now reside in a separate folder, which simplifies periodic syncing to external hard drives or network-attached storage servers on home networks. The system prevents duplicate files by storing identical media only once, reducing storage demands when mirroring backups.
Hosted Backup Tiers and Linked Device Syncing
Signal offers a free hosted backup tier that secures text messages alongside the most recent 45 days of media. Subscribers paying a monthly fee gain up to 100GB of media storage. Users with linked devices can also bridge historical gaps without downloading full archives immediately. When opening a message thread on a newly linked laptop and scrolling beyond the 45-day threshold, Signal Desktop securely requests missing files directly from the primary device as an end-to-end encrypted attachment. Paid subscribers can offload older photos and videos while leaving a low-resolution thumbnail on the device. According to Signal, this setting shrinks 5GB of unused media down to roughly 600MB.
Security Mechanisms for Local and Hosted Backups
Hosted backups rely on a dual-protection scheme combining the user’s recovery key with a daily rotating key stored inside a Trusted Execution Environment (TEE). Signal states that TEEs currently provide the optimal defense for supplemental keys, though this secondary key cannot decrypt a backup independently, thus ensuring forward secrecy. Because on-device backups reside on user-chosen drives or cloud services, they bypass TEE protection entirely. Instead, a single recovery key unlocks all historical local archives, prompting Signal to issue strict warnings against sharing the key.
Disappearing Messages and Local iPhone Transfers
Messages configured to vanish within 24 hours are excluded entirely from both hosted and local backup formats. Expired disappearing messages are automatically bypassed during backup restoration, though Signal advises users to implement shorter expiration timers directly within on-device backups if needed. Alongside these backup updates, the iOS release introduces a reworked iPhone-to-iPhone transfer tool operating over a local, end-to-end encrypted Wi-Fi Aware connection. Signal confirmed that these additions conclude the initial phase of its backup project, though development teams are actively building non-backup features.
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