More speed on mobile connections

The new queue control reduces usage when a limited network is detected.

Mobile links drop, they do not fail cleanly

A transfer on a desk network either finishes or it stops with a clear error. On a phone, in a car, or on a train, the link disappears for a few seconds and comes back as a different address. The file is not corrupt. The transfer was abandoned halfway and, unless something resumes it, the person thinks the archive lost the photo.

The change is that a mobile transfer now continues from the last confirmed piece when the same device comes back, instead of starting the file again. The original on the camera roll is not touched. The copy in the archive grows until it matches, and only then does the activity history call it complete.

What you should see

On a large video, the progress pauses when the signal goes, and it continues when the signal returns. It does not jump back to the beginning. A small photo still finishes in one step, because resuming a file that was already done would be theatre. If the phone is offline for long enough that the session expires, the next attempt starts clean and says so, rather than pretending to continue a transfer the server has forgotten.

The archive owner can see, in the activity history, that a file arrived in more than one session. That is a fact about the network, not a warning about the file. The completed file is the same file it would have been on a quiet wifi.

What this does not fix

It does not make a crowded mast faster. It does not keep a transfer alive through airplane mode for an afternoon. It does not upload a file the phone has already deleted from its camera roll. If the source is gone, the history says the source is gone.

Battery savers that kill the app in the background will still kill the app. The transfer resumes when the app is opened again, from the last piece the server accepted. You do not have to pick the file a second time.

The change is on every current plan. A phone that never resumes is worth a note to the help centre, with the model and the network you were on.