You can tell what version of dcm2niix created your BIDS file by looking at the tag "ConversionSoftwareVersion":, this should read something like "v1.0.20171215 GCC6.1.0" - you can see if this is the latest release by checking here 
  https://github.com/rordenlab/dcm2niix/releases
If you have a recent version of dcm2niix on MacOS or Linux, you might also try running "dcm2niix -u" which attempts to check if an update is needed. I assume the recent versions will report multiband information, but you can always extract this from the slicetiming field, e.g. it is x2 in your example