How to sync your data
Growth records are health data, and health data is private. For this reason the app does not ever transmit your data to a server and there is no syncing by default.
However, thanks to the external file feature of Growth version 2, you can store this data in the cloud file service of your choice.
I recommend that you use iCloud Drive, as it is readily available and, being an Apple service, is the most trusted and convenient service on iPhone and iPad. But you can also use another service such as Dropbox, Google Drive, Microsoft OneDrive or Tresorit.
Setting up sync via iCloud drive
In the child’s profile, tap on Storage at the bottom of the page, then select “External file”. Tap Done and choose a folder inside iCloud Drive. Your child’s data is now synced via this file.
Setting up your other devices
Open the app, then tap on the folder button at the top. Locate the file you saved above. Your child’s data is now listed in the app and you can open it to edit measurements, which will be synced to other devices via its file.
Why this is not available for free
Free users are limited to one child. If file access was available for free then anyone could use files to track multiple children without purchasing the upgrade.