There is a field of improvement in the recognition of “offline” state.
Whenever the connection to the WiFi router is given, but the data is not possible to be put on the server (on my device it occurs every day or second day – still do not know why), Model D does not recognize it itself as “being offline”. Thus it does not collect data into the buffer for the purpose of putting it through “sync” command later on. Sadly whenever I check the device’s state on the webpage in the morning (it’s a curiosity that the disconnection to the uradmonitor.com page occurs always shortly after 4:00 am), it is shown as “online”. The correct status “offline” is shown after I come from work and check the data again. Here I can see, that no data has been put onto the server since 4:40PM)