If the newest version of IE isn't your cup of tea, you can opt out by either disabling updates in IE or blocking the update on your computer with a specific Microsoft tool for the task.
If Internet Explorer has already updated and you want the old version back, you can rollback by uninstalling the update. Before you can extract the files in the package, you must accept the user agreement. You will have to use a command prompt to run the blocker toolkit, so extracting the files to a new folder in the C:\ drive is easiest to remember.
As such, it could very easily be installed inadvertently.
Fortunately, for those of you who want to prevent that possibility, Microsoft has created the Internet Explorer 9 Blocker Toolkit.
You may have your own reasons for doing so – but if you do wish to disable Internet Explorer 10 automatic update, you can do so easily.