Windows Phone 8.1 is certainly proving to be a huge OS overhaul than mere some cosmetic changes and nearly all settings, start screen and native apps have some changes to report. There has been a surge of leaks post Windows Phone 8.1 SDK release to some developers. For your convenience, all Windows Phone 8.1 changes, which are revealed yet, are collated in one place on this page. You can go through full changelog revealed from various leaks followed by leaked screenshots and even hands-on leaked video, where available.
Bookmark this page so that you can keep yourself updated with any new changes that are revealed. Here you go,