In version 8.30, Signal completed the availability of encrypted conversation backups on Android, iOS, Linux, macOS, and Windows, with support for local backups without size limits and direct data transfer between iPhones.
Signal completed the first phase of its secure backup project with the release of version 8.30, which adds encrypted local backups on iOS and desktop applications and unifies the backup format on Android so that it is cross-platform. The feature is now available on Android, iOS, Linux, macOS, and Windows.
Backups allow users to create a copy of their conversations and restore it on another device if they lose their phone. In both available options, the system relies on end-to-end encryption and a recovery key required for decryption.
Two Backup Options
Signal offers backups hosted by the company, but it imposes on free users a limit of 45 days of media and 128 kilobytes per message, while paid plans provide capacity of up to 100 gigabytes. Local backups on the device, by contrast, impose no size limits.
Hosted backups also use an additional key that changes daily within a trusted execution environment, providing additional protection and forward secrecy. By contrast, the local backup recovery key can decrypt all previous backup files it created, regardless of where they are stored. This makes protecting the recovery key a central security concern, particularly since threat actors began targeting it after the first feature was introduced.
What Changes in Practice?
When a new device is linked to the primary device, Signal will restore old attachments that are not present in the conversation history. Media is also now stored separately from the backup archive, and duplicate files are stored only once, reducing backup sizes and synchronization tasks.
Paid subscribers can delete old media from local storage and retain only thumbnails, while automatically retrieving the full versions from hosted backups. Messages set to disappear within 24 hours are excluded from both backup options. If someone uses hosted and local backups together, creating the former does not delete the latter, but expired messages will be skipped during restoration from the local backup.
Direct Transfer Between iPhones
iOS version 8.30 also adds direct transfer from iPhone to iPhone over a local, end-to-end encrypted Wi‑Fi Aware connection, which Signal says improves speed and reliability.
The update is significant because it expands the restoration of encrypted conversations from an Android scenario to the entire Signal ecosystem, while keeping recovery keys beyond the service's ability to decrypt backups. However, this protection does not eliminate the risks of losing the key or having it fall into the hands of an attacker; possession of the local backup key provides access to all files encrypted with it. Signal says that after completing this phase, its engineers will move on to improving systems other than backups.