Practically from the new firmware version 27.14 onwards, the device is terribly capable of freezing up. In addition, the battery level is terribly distorted. It is enough that when turning the device off the battery level is e.g. 22%, then turning the device on again the next day already shows 19%. Where the battery level magically disappears. And this does not mean putting the device into sleep mode, but switching it off. It can even lower the battery level even further, which I have already had the case once, when when switching off the device was 30% and the next day when switching on 11%. It's getting worse and worse, the newer the firmware the worse the performance. On top of this, there is the problem of connecting sensors that have already been paired previously. One day everything connects perfectly and the next day the di2 does not detect or power meter etc.