Indicative Roadmap for Windows 9, the next update after Blue.
Windows 9 Beta (7 January 2014)
Windows 9 Release Candidate (July 2014)
Build 2014: Windows 9 RTM (October 2014)
November 2014: Windows Release 9
Testers have got build 9319.0.130208-1820 from Winmain / FBL_EEAP branch
According to Win8China, Internet Explorer 11 is currently in development and will be included in the next major update to Windows named "Windows 8.1" (aka 'Blue') that is expected to be released this summer.
According to fresh rumors, Microsoft has switched to kernel version 6.3 in the upcoming update to Windows. Windows 8's successor's screenshot has been leaked to the public by the famous underground WZor team: