The Rocketbook app is not cloud connected across your own devices. So even if you have the same log-in on multiple devices or if you get a new phone, the only scans that show up in your history tab are the scans taken with that specific device. This is also the case with destinations.
For user privacy purposes, Rocketbook does not store any of your notes on our own servers. Your notes are either on your own device or the cloud service you have sent your notes to.
Unfortunately, this also occurs when the app is uninstalled and reinstalled, or logged out of and back into.
We do, however, recognize the demand for this, and we hope to address device cross-syncing and data back up capabilities in a future app version.
We invite you to show your support for that addition by upvoting it on our suggestions page at ideas.getrocketbook.com, that specific idea right here. Until then, all of your scans will still be safe and accessible in whichever cloud destination(s) to which you've sent them.