The Australia Telescope Compact Array is currently in the process of being upgraded to the new BIGCAT (Broadband Integrated GPU Correlator for ATCA) system. BIGCAT will provide a spectral resolution of at least 0.6 kHz, significantly improve the reliability of the ATCA correlator and also provide more flexibility, with many more options for frequency resolution and integration times, and the ability to change quickly between different correlator modes. BIGCAT will come with a new version of the ATCA observing program caobs, a new scheduling tool, a new file format (replacing RPFITS with ASDM — ALMA Science Data Model), and a new archive (moving from ATOA to CASDA). The ASDM data format is a Measurement Set (MS) filesystem which is natively compatible with CASA. Users will be able to use CASA for data processing and analysis, or export to FITS format to be reduced using miriad. Further information and training for observers will be provided as BIGCAT implementation and commissioning progresses.