How do I view the history data? How long is the history data stored?

To view the history tracking data on the map, from the "Tracking" page, click the unit icon on the map and select "View history data", or click the unit's name in the table below the map. You can then change the time range on the history data page.

The history data is stored for 2 months then gets deleted from the system automatically. To backup your data, see here.