id Quantique has released new firmware, version v4.0, for the id201, offering new functionalities such as: adjustable detection probability (adjustable to 10, 15, 20 or 25 per cent, or user-defined); adjustable dead time (0s, 1us, 2us, 5us, 10us, 20us, 40us, 60us, 80us, 100us); user-defined gate width (from 0 to 20ns); and an increased maximal trigger rate. The internal trigger can be 1kHz, 10kHz, 100kHz, 1MHz, while the external trigger can be up to 8MHz.