I've prepared for XWiki SAS's Seminar a presentation reviewing the improvements and new features we added inside XWiki Enterprise between version 2.4 and version 5.1.
For features that existed before 2.4 there is a comparison view of how it looks now and how it looked back then. I've also listed the people that were involved in making the features come true.
In my opinion the review displays the progress XWiki Enterprise has gone through and also shows the collaboration between our community members in making proposed things into reality.
For a complete list of what we integrated in this time frame make sure you read our Release Notes. Also for the ones that don't recognize our community members, please check our Hall of Fame.