Google seems to be pushing the Chrome OS 63 update out to its Pixelbook and Samsung's Chromebook Pro and Chromebook Plus on the stable channel. The update recently started hitting some machines, though reports of the update are not widespread just yet. This update has been on a somewhat slow rollout, with the Pixelbook and the Samsung Chromebooks Pro and Plus being among the last to receive the update. On the stable channel, the Acer Chromebook 11, HP Chromebook 11 G5 EE. and Mecer V2 Chromebook are the only ones left still sitting on Chrome OS 62.
This update does not boast any new features, but rather focuses on implementing a wide gamut of security patches and bug fixes. Key vulnerabilities and critical security risks are all patched up in Chrome OS version 63, and notably, the new version of Chrome OS includes fixes that nullify the newly revealed Spectre and Meltdown vulnerabilities, which affect all Intel and ARM processors. The update actually started going out to some Chromebooks before the bug was made public; the fixes are not based on the information that was released to the public by various companies, but rather on characteristics of the vulnerabilities that were discovered by Google at earlier stages. The Intel version of the vulnerability works on the principal that dependent code is checked for malicious intent after it's already been run, and the ARM version uses speculative execution for privilege elevation by slipping past the processors' built-in security. All of these vulnerabilities have now been patched up on Chromebooks running Chrome OS 63 and up, and Google has been working on patches for Android as well.
Chrome OS 63 has been available in the Beta channel for some time now, and Chrome OS 64 is already in the works, being prepared for release into the Stable channel in the near future. In the Dev channel, version 65 is already being worked on. Chrome OS 64 tweaks the OS' multitasking capabilities under the hood to make multiple apps run smoother side by side, among other features. Stronger protections against malicious ads and an API that allows webmasters to observe page and element resizing is also on board. Chrome OS 65, meanwhile, is just beginning to be developed, and as yet, new features have not materialized in any substantive way.