Although Google described the new version as a mix of optimizations and bug fixes, the real significance is that the new OS will be the baseline version that will be rolled out to partners interested in developing phones and tablets around the new OS. It also appears to possibly include Facebook Ticker-like functionality.
"Going forward, we'll be focusing our partners on Android 4.0.3 as the base version of Ice Cream Sandwich," Xavier Ducrohet, the Android SDK Tech Lead, said in announcing the new version. "The new platform will be rolling out to production phones and tablets in the weeks ahead, so we strongly encourage you to test your applications on Android 4.0.3 as soon as possible."
In addition to incremental improvements in graphics, databases, spell-checking, Bluetooth, and other features, the new OS includes a new social stream API.