EllisLab/CodeIgniter — pull request #2098 by AndrewPodner (2012-12-25 21:01:16+00:00)
Title: Issue #623 : Detect IE Compatibility Mode

Uses the reported browser version number and trident engine version number to determine if Internet Explorer is running in compatibility mode. If compatibility mode is detected, the browser will be appended to read "Internet Explorer (Compatibility Mode)" and the version will be adjusted to the actual version of IE that is being used based on the trident engine version

Additionally added a method to return a boolean value whether or not compatibility mode has been detected.