Hi Rob,
DPP 4 is fully released, but 64 bit only and ONLY supports RAW from full-frame cameras such as the 1 series, 5 series and the 6D. And, from the other RAW files I have, it must only be the Canon EOS-1D X, EOS 1-D C, EOS 5D Mark III and EOS 6D.
DPP 3 will be updated for all other cameras in 32bit format.