The funny thing is, the changelog for this beta doesn't list any tracking updates.
This is a "Tool update" for what appears to be a completely undocumented tool to attempt recalibration of the headset's cameras: ViveEyeOnTheFly.
Go to your Viveport installation directory, then \VIVE\Updater\App\ViveEyeOnTheFly. Run CameraCalibrationTool.exe. If you have a 17 inch display or larger, you can do this calibration thing while holding the camera infront of your display. This is the tool that got updated in this beta release.
I did this tool, and it said it completed calibration successfully.
Unfortunately, I noticed absolutely no tracking improvement after doing it. My biggest issue with tracking still remains: the headset wobble which makes me nauseous.