I just downloaded that latest version  and I'm getting the following error in IE11 (works fine in IE10):

Unhandled exception at line 3, column 262200 in eval code

0x800a1391 - JavaScript runtime error: 'HTMLElement' is undefined

As a result the toolbar displays, but the dropdowns are greyed out. The editor window displays a hand with a no-entry sign pointer and can't be used.

This is the .NET version (6.7.0.0 Build 2013-10-22)