New details about Windows 9 have leaked

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

Internet Explorer 11 will be shipped with Windows 8.1 (aka ‘Blue’)

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.

IE11