You can force the data-transfer from the app to the tracker by dragging down the dashboard screen in the app. You will see two sentences appear:
Last update - tracker : xx-xx xx:xx
Last update - server : xx-xx xx:xx
These sentences give you feedback on the last date & time which the data was transfered from the tracker to the app and from the app to the server. When dragging down the screen the sychronisation of data is force to take place immediatly and will updated shortly.