Now that Chrome 17 has made it safely to the stable channel for Chromebooks, Chrome 18 has graduated to the beta channel to take its place. Chrome 18 has spent several weeks in the dev channel already and comes with several new features.
Chrome 18.0.1025.32 Beta, part of Chrome OS 1660.34.0, comes with a brand new Flash Player, the Pepper variant that comes with Chrome and Chrome OS.
Wi-Fi stability has also been improved in the latest build, Google boasts. At the same time, Chrome 18 also brings better system hardening, for improved security.
The File Browser has received some more improvements, it was updated in Chrome 17 as well.
This version of Chrome landed in the dev channel a couple of days ago, but it was deemed stable enough for it to be pushed to the beta channel without any further changes.