PicoQuant GmbH has introduced version 1.2 software for use with its HydraHarp 400 time-correlated single-photon-counting system. The program provides a real-time correlator for fluorescence correlation spectroscopy (FCS) that calculates two autocorrelations and the cross correlation between two photon streams simultaneously. The new release supports Windows 7 and the latest HydraHarp hardware, with up to eight timing input channels. Each channel produces 1-ps resolution at a processing rate of 12.5 million counts per second per channel. All channels operate independently but with a common crystal time base. A time-tagged data collection mode provides a stream of individual timing events to the host computer that can be processed and analyzed for photon burst detection, coincidence correlation or for combined measurement of fluorescence lifetime and FCS.