on IE 11:
Mozilla/5.0 (Windows NT 6.3; WOW64; Trident/7.0; Touch; rv:11.0) like Gecko
it detects engine_version, browser and browser_version as empty strings:
{"platform":"windows","device":"","engine":"gecko","engine_version":"","browser":"","browser_version":""}
on IE 11: Mozilla/5.0 (Windows NT 6.3; WOW64; Trident/7.0; Touch; rv:11.0) like Gecko
it detects engine_version, browser and browser_version as empty strings: {"platform":"windows","device":"","engine":"gecko","engine_version":"","browser":"","browser_version":""}
FYI: http://msdn.microsoft.com/en-us/library/ie/bg182625%28v=vs.85%29
Thanks!