Signal 8.30 brings encrypted backups to every platform

Signal has finished the job it started last September. In a blog post published on Monday, 28 September, the messaging app set out a year of work on Signal Secure Backups and confirmed that the improvements ship on all platforms with the launch of iOS version 8.30.

What has actually changed

The headline addition is on-device backups. They arrive on Signal Desktop and Signal iOS for the first time, and they are rebuilt on Signal Android so that all three use the same cross-platform format. The practical result is that a backup can be created on one platform and restored on another, across Android, iOS, Linux, macOS and Windows.

Signal has also fixed the thing that made local backups slightly absurd on Android. Older backups rolled everything into a single archive, so a daily snapshot quietly ate your storage. Media now lives in its own folder, duplicates are stored once, and a new optimisation setting offloads unused photos and videos, leaving a small thumbnail behind on the device while the full-size copy waits in a paid backup account. Signal's own example is 5GB of unused media shrinking to roughly 600MB.

Attachment backfill handles the gap between the free and paid tiers. A paid plan covers up to 100 gigabytes of media, while the free plan backs up text messages but keeps only the last 45 days of media. On a freshly linked laptop, Signal Desktop can now pull any older attachment straight from your primary device, end-to-end encrypted, instead of asking you to forward yourself your own messages.

Why a backup is the hard part of a private messenger

End-to-end encryption is comparatively easy to sell and famously awkward to live with: if the keys only exist on your phone, then losing the phone means losing the history. Signal's answer has been to let users choose, with an encrypted copy that the service cannot read, either on their own hardware or in a paid account.

Making that copy portable across five operating systems is the unglamorous work that decides whether people actually switch phones and stay. A messenger that punishes you for buying a different handset is a messenger that gets deleted.

Our opinion

This is Signal doing the boring, necessary thing properly, and it deserves more attention than it will get. Everybody applauded when the privacy crowd refused to hand over encryption keys; almost nobody noticed that the price of that refusal was a decade of users losing their messages whenever a screen cracked. On-device backups that move between Android and iPhone remove the last honest excuse for staying inside a platform you do not want. The 45-day media limit on the free tier is still stingy enough to be annoying, and Signal knows it — attachment backfill is a workaround for an artificial ceiling, not a feature. Pay for the plan, or keep forwarding yourself holiday photos. At least now the choice is yours.