Microsoft he pushed forward the upcoming Windows 10 May 2019 feature update Update in the final stage of development Release Preview ring.
The company announced just a few days ago that it would change its routine procedure distribution of feature updates to Windows 10 systems, and instead of making the update available immediately, decided to do another round of testing in the Release Preview ring.
Release Preview is one of the available Windows Insider rings. The other rings are Skip Ahead, Fast Ring and Slow Ring. All of this differs in the frequency of builds but also in their stability.
Promoting the upcoming Release Preview Ring marks the final step in the development process.
Microsoft plans to release the Windows 10 May 2019 Update at the end of May, delayed by about a month due to the new process and because the last update that came out, (Windows 10 version 1809), presented too many problems to the intrepid installers.
The reason for the feature updates changes with May 2019 Update release. You can read about all the changes from the link below:
Microsoft: AI is not enough for Windows 10 updates