The data storage format is slightly different in iOS and Android; it is impossible to sync or migrate data directly between iOS and Android.
iOS and Android devices can be synced via our web version. It is a subscription-based service as we need to store data on our server hosted on Microsoft Azure and convert the data structure on the server.
The trial should be good enough if you want to convert data once. You don't need to subscribe after you convert data. You need to log off from those devices.
Please always back up ATracker data before data migration.