All your secrets are stored on your media card in /sdcard/secretbox.

Connect your phone to your PC and mount it as an external hard drive. Once mounted look for secretbox directory on newly mounted drive.

Copy entire directory to your PC for backup.

To recover the backup or to transfer your secrets to the new phone copy secretbox directory to your new phone's /sdcard/ directory.

Secret Box and Secret Box+ will pick up your database if it finds it.