You can enable Dropbox sync in ATracker -> Settings-> Settings.
If you want to sync data among multiple devices, please select "Migrate data into cloud" when you enable the Dropbox sync on the first device (the device which you want to keep all records), and select "Delete local data" on other devices (which data will be overwritten by the data on the first device).
It might take some seconds / minutes to enable the sync, depend on how much data to sync and the network speed, please do not force stop / kill ATracker App in the process.
By default, if the Dropbox sync is enabled in ATracker, the daily backup will be enabled. The daily backup can be enabled / disabled in the device settings.
Note: User needs to have Dropbox app installed on device as well for authentication process. The authentication via Safari is not enough.