Microsoft has out press invites for an event they re holding on June 24 at 11 AM ET. Invitation includes a reference to what looks to be a new logo for Windows. CEO Satya Nadella previously confirmed that Microsoft is working on the next generation of Windows. The Sun Valley Update is expected to hit production channels in October/November and it would be an optional update. Reports suggest that the Sun Valley features will be released to Windows Insiders in late June or early July. Microsoft employees have already started self-hosting the preview builds.
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-to-announce-windows-10s-successor-on-june-24/