Posted by O.Sommer
Since the beta of IE11 and since Win8 got released with IE11 user complained about OWA Premium, which is the name for the fancy Outlook Web App Version where for example it is possible to use right clicks and other stuff that helps a lot being more productive with email, not been loaded, but instead they got the basic OWA experience that looks a lot like OWA from Exchange 2003 or older and is way less productive to use!
Microsoft KB 2866064:
Can't load OWA Premium by using Internet Explorer 11 in an Exchange Server environment
(german: OWA Premium kann in einer Exchange Server-Umgebung mithilfe von Internet Explorer 11 nicht geladen werden.)
Image: OWA Premium of Exchange 2007
Image: OWA Basic of Exchange 2007
Recently administrators who updated their Exchange 2007 Server with the latest RU13 which is available here
Update Rollup 13 for Exchange Server 2007 Service Pack 3
might have noticed that user complaints stopped and in fact users now got their OWA Premium experience back, despite the fact that Microsoft announced that Exchange 2007 is in extended support for some time now already and therefore would only get security updates but no non security relevant fixes (like this IE11 OWA issue)!
Nevertheless RU13, or CU13 as it sometimes is called also, silently, because nothing of this is mentioned anywhere nor does Microsoft support services have had any information about it, patches two files to integrate a fix for the IE11 issue:
jscript and microsoft.exchange.clients.owa.dll
This got discovered and proven with reverse engineering RU13 by the German MS Support Team in a Microsoft Support Call I recently had for a customer.
Microsoft Services escalated this information to update the KB and RU information to include information about the fix like I would have expected in first place.