Moving to a new Android phone does not affect the photos already on your Ultimate Backup — they stay exactly where they are. What changes is what the app on the new phone knows, and on Android that is worth knowing before the first backup runs.
Before you switch
While you still have the old phone, run one more backup and let it finish — How do I know if all my files were backed up? shows what a finished backup looks like. Check whether contacts backup is switched on while you are there: on Android it starts off, and only what was backed up can be restored later.
When it has finished, eject the drive before unplugging it.
Setting up the app on the new phone
Install the app, then sign in with the account you used on your old phone. If you do not remember its password, you can reset your password. If you no longer have access to that email address, create a new account instead — your backups are not tied to your account, so nothing already on the drive is lost. See Do I need my account to reach my files?
Choose your product when asked.
Then open the Drive Picker and choose the top level of the drive, allow photos and videos with Allow all rather than picking individual items. App Setup for Android has the screenshots, and Got a new phone? covers which drives fit which port.
What the first backup does
The drive keeps each Android phone's backups in a folder named after its model — "Galaxy S26", for example.
A new Android phone starts over. Restoring the phone from Google or Google One does not bring the app's record of what it has already backed up, so the first backup copies your files again. The quickest way to see where you stand is the big button on the Home screen: Start Backup means the app has no record yet and will copy everything, while Resume Backup means it found one. Start Backup or Resume Backup: what's the difference? explains the difference.
Where those files land depends on the model. A different model gets a folder of its own, which means a second full copy of your library on the drive, so check there is room for it. The same model writes into the existing folder, where a file of the same name is written over rather than doubled.
Does a second drive start where the first one stopped? covers the same ground for a new drive.
Getting your photos and contacts onto the new phone
Open Settings, then Restore Files. The list holds every device that has backed up to this drive, so your old Android phone is there — and so is any iPhone you have backed up.
Restored files are placed in a folder called UB Restore, inside Pictures, Movies, Music or Download depending on the file type, and the app does not back them up again afterwards. Copy Files from Ultimate Backup to Android has the full steps.
For contacts, select them in the same list and tap IMPORT — your phone's own Contacts app finishes the job. The Restoring contacts section of Copy Files from Ultimate Backup to Android covers that.
Coming from an iPhone
An iPhone's folder restores in exactly the same way, contacts included. The drive plugs into the new phone's USB-C port.
KeepSafe
KeepSafe follows your account, so signing in with the same email address is usually all it takes, and it switches itself back on afterwards. If your subscription does not appear, use RESTORE PURCHASE; billing stays with Google Play either way. KeepSafe Overview covers the rest.
If you need any additional assistance, please contact Ultimate Backup support.