Despite the fact that Android 4.0 hasn't yet been rolled out to most devices, a new version of the Android code is hitting the Android Open Source Project repository servers today. Of course, the 4.0.4 update only has bugfixes, but according to the changelog these bugfixes do include hundreds of stability and performance fixes that will doubtless improve the Android 4.0 experience.
Eventually, carriers and manufacturers should be able to push this update to their own hardware, but for now the only devices to have already received the update is the Wifi Xoom tablet, GSM Galaxy Nexus and the T-Mobile Nexus S. The rest of the Nexus phones (other than the Nexus One) should get the update in short order, but for other devices it is anyone's guess when the official update will come out.
As usual, then, the people this really helps are open source developers. Sooner than most manufacturers get it out, custom ROM developers will likely have the latest Ice Cream Sandwich 4.0.4 builds ready for most popular devices. In fact, the Cyanogenmod team, makers of the most popular custom ROM, will also merge the 4.0.4 code into nightly builds of Cyanogenmod within the next few days, allowing supported devices to update much earlier than they would otherwise be able to.
It may just be a minor update, but it's always nice to see Android getting better. Also, the focus on squashing bugs without any changes is an important part of the development process, especially because Ice Cream Sandwich has plenty of little bugs that need to be dealt with. Anyways, after the fiasco that was closed-source Honeycomb, new Android source code is always welcome.[Android Building]