Microsoft's Windows 10 April Update was supposed to be out earlier this month but got delayed at the last moment due to an issue with systems hangs on a select subset of systems. Previously known as the Windows 10 Spring Creators Update, the final version of the new Windows 10 build is now anticipated to hit the web on May 8.
According to a tweet posted earlier, in what is claimed to be an internal memo from a Chinese retail vendor, it shows that the Windows 10 April Update will start rolling out on May 9, which falls on a Wednesday in mainland China. It's important to note that due to the time difference, it'll still be Tuesday May 8 in the United States, so the rollout could start then, while it will be May 9 in China.
There's no official confirmation yet, but May 8 seems like a logical date. The whole naming is messed up though, Microsoft will be releasing a build version 1803, called April Update, in May!