Installed this Win 10 update 4 hours ago and I can report that it gives me a noticeable improvement for the few minimal audio issues that bothered me with Cubase.
Example… I no longer hear any audio start delay when first starting Cubase and immediately playing a project.
Regards 
Hi,
Thank you for the info. I’m glad to hear this.
As I mentioned in another thread, this update fixed all the latency issues I was measuring on the Windows partition of my Z390/i9 setup.
In my case, 1903 corrupted my soft-elicenser and I had to reset/wipe it (using utility provided by Steinberg support) and reactivate licenses. I haven’t noticed any audio/latency/performance improvements. I have noticed that launching Cubase by opening a project from file-explorer, intermittently results in the app launching, but project not opening. So in summary, Windows update 1903 can impact Cubase function/performance and i do not recommend doing it in the middle of a job!
Just so there is no confusion…
This topic is discussing an update (KB4505903) for an already installed Win 10 version 1903. The link I provided above explains the improvements/fixes for audio issues seen with the original Win 10 1903 upgrade.
Regards