does anyone know if we can use last years labview software for this years competition
If you are asking if you can use last year Robot code then YES
If you are asking if you can use last year versions of LabVIEW then NO!
You will need to use the version of LabVIEW that you got in your kit of parts.
This year for FRC 2016 you will be using LabVIEW 2015.
Last year for FRC 2015 you used LabVIEW 2014.
LabVIEW 2014 can not open and run the VIs in the FRC 2016 update.