Microsoft is preparing to release the May 2019 cumulative updates for Windows 10, as part of its monthly Patch Tuesday.
So tomorrow all versions of Windows 10 (and other Microsoft products) will be able to receive these updates for the month of May. The updates, as you may know, contain many security improvements, as Microsoft uses the Patch Tuesday cycle to fix vulnerabilities in its products.

Additionally, some non-security bug fixes are included to improve Windows 10 performance.
Of course, later this month, Microsoft is expected to release the new Windows 10 feature update called the May 2019 Update, or version 1903, to everyone. The update is currently being tested in the Release Preview ring of the Windows Insider program.
This update will be rolled out gradually, so some devices will get it earlier than others.
Microsoft says this approach is necessary to avoid too many problems, since if you think about it, the first devices continue to test the operating system while the company continues to resolve the problems that arise.
Cumulative updates have now caused a lot of problems for end users at times. So if you're thinking of updating tomorrow with the May 2019 cumulative updates as part of the monthly Patch Tuesday, it would be best to wait a few days.
