Turn your Tentacle SYNC E around and check if you find a sticker with the serial number on it. The Mk2 version has it printed outside the housing. Please update to the latest SYNC E mk2 Firmware 1.1.0
The SYNC E mk1 Firmware update 2.0 is available through the desktop version of the Tentacle Setup App, as well as the display of the serial number.
Tentacle SYNC E MkII
Tentacle SYNC E MkI