The CDMA version of the Nexus S finally gets its long-awaited Ice Cream Sandwich update. In fact, the ICS version listed after flashing is version 4.0.4.
This, as opposed to 4.0.3. is not a part of any official Android build, and may likely contain functionality yet to be announced by Google. As of now, the only confirmed update found in 4.0.4 is for WiMax drivers.
If you’re willing to take the risk (and have root access), XDA has confirmed success when updating via fastboot.
Apart from the original Nexus S and the Motorola XOOM, the Nexus S 4G is the only other device that will receive the ICS update directly from Google.