A now-removed Microsoft Azure support document had revealed Windows 11 as the upcoming version of Windows two weeks ago. Microsoft is also running an advertisement in the Google search results promoting their upcoming Windows event on Thursday, June 24, at 11 AM EST. Microsoft has since removed the entire GitHub repository containing the reference to Windows 11, but we will know for sure in just three days. The advertisement is not necessarily confirmation of the name, it shows that Microsoft is targeting the ‘Windows 11’ keyword for their upcoming event.
Source: https://www.bleepingcomputer.com/news/microsoft/windows-11-name-confirmed-for-two-weeks-and-everyone-missed-it/