There is a feature that was 'Device Migration' to transfer your previous files to the new phone in setting page. 

But if your old phone is lost or damaged without doing any backup or sync your files to cloud in GalleryVault, you will unable to get your files back. If you have synced previous files to cloud and keep them being done until icon “√” appears in the lower-right corner of the thumbnail image, please login with your previous account in your new phone and re-link to cloud, it will be synced to your device automatically.

To make sure security of your own private files, we cannot have the right to back up your files in our server. Please remember to back up important files in advance next time.