Our recommended solution for your data security:
Turn on the sync feature. By doing this you can save the latest data on the Grid Diary sync server and switch between different devices at any time. If you are not a member or just want to use standalone mode, you can skip this suggestion.
Turn on the automatically created data snapshot feature and allow it to save on iCloud. This way you can always get the historical data of the latest 30 days.
Export JSON files every month and save them to a secure location (such as iCloud Drive, Dropbox, etc.).