The fourth Chrome 66 build for Chrome OS has landed in the Chrome OS Beta Channel today. Build 66.0.3359.102 (Platform version: 10452.54.0) is now available for most systems, bringing bug fixes and performance improvements. You can manually check for the update by typing chrome://help in the browser bar if you have a Chromebook in the beta channel.
As most readers know, the Chrome OS Beta Channel is the last step before a new build of Chrome arrives for everyone in the Stable channel. Chrome 66, which is essentially a maintenance build for the platform, is slated to go to the Stable Channel on or around April 25th. There will likely be a fifth and final beta build next week.