Anyway to synchronize data from Tag via web application (to cloud).
Like you can get data to your phone with app & Bluetooth?
In case connection is lost, measurements seems to be lost too. Even you can of course synch those to Ruuvi app.
The Ruuvi Gateway does not support GATT connection to tags. We might add a local buffer to Gateway so it could store the data while there is no connection and then upload it all, but that feature is far down in the roadmap