Let's make sure 1SE is backed up on your device! We'll be using iCloud but you can do all this with iTunes also. If you have a 1SE PRO account, follow these steps to back up your data.
Back up your device with iCloud
Before you begin, make sure 1SE will be included in your iCloud backup by following these steps:
Now, make sure your phone is fully charged and connected to wifi.
Go to Settings > [your name], and tap iCloud. If you’re using iOS 10.2 or earlier, go to Settings, then scroll down and tap iCloud.
Scroll to APPS USING ICLOUD and toggle 1SE on. If you’re using iOS 8 or later, make sure iCloud Drive is enabled.
Tap iCloud Backup. If you're using iOS 10.2 or earlier, tap Backup. Make sure that iCloud Backup is turned on.
Tap Back Up Now. Stay connected to your Wi-Fi network until the process completes. This may take a while.
Yay! Congrats, you now have a backup with 1SE to restore from. If you'd like a more detailed step by step for iCloud or iTunes backup. Check out Apple's help article on it.
VERY IMPORTANT: Please keep in mind logging into iCloud on your new iPhone isn't the same as an iCloud backup. 1SE is NOT saved in your iCloud account. Only basic data like notes, mail, and contacts are. You'll need to do a backup via iCloud or iTunes.