So you have this well known security issue called content sniffing in MS IE 6. No one really cares about that anymore right? Unfortunately, when you are a top 5 website, then you kinda have to care, since 3,46% of the readers of Wikipedia, so a whopping 13.88 million of the unique monthly visitors still use Microsoft Internet Explorer 6. You try to fix this bug. Three times , causing three software releases ( 1.16.3 , 1.16.4 , 1.16.5 ) in 4 weeks. And then by accident, it becomes so strict that it breaks many of the requests for all Internet Explorer versions , simply because the url contains a dot. Sigh.... THIS is why you should help all your friends to get rid of IE6 .