Canon has released updated firmware for three of its digital SLRs and the WFT-E2/E2A wireless transmitter.
Version 1.2.4 for the 5D Mark II adds support for the WFT-E4 II/WFT-E4 II A transmitter and "corrects a phenomenon in which visible noise may appear in images taken by continuous Bulb shooting."
Version 1.3.0 for the EOS-1D Mark III and v1.2.0 for the EOS-1Ds Mark III enable these cameras to work with the WFT-E2 II/WFT-E2 II A. Also, v2.0.0 of the firmware for the WFT-E2/E2A allows this transmitter to function with the soon-to-be-released EOS-1D Mark IV.
Links: Canon EOS 5D Mark II v1.2.4 | Canon EOS-1D Mark III v1.3.0 | Canon EOS-1Ds Mark III v1.2.0 | WFT-E2/E2A v2.0.0