We cannot say that it’s just and upgrading to its predecessor IE8. Microsoft rebuild it and gave it instincts like high speed, graphics improvements, UI improvements, Hachamovitch touted its advanced support for HTML5, accelerated hardware and accelerated the adherence to web standards. They tried to rebuild its every corner. They claim for providing it with security features as well by including tracking protection against malwares.
You can download its final version from BeautyoftheWeb.com at midnight ET/9:00 PMPT.