Microsoft has been quietly been making changes to its Bing search design and experience for Windows Phone 8 owners. While the company has not issued a formal press release or blog post about the updates, they started appearing on some Windows Phone 8 devices in the U.S. Friday, Aug 2, according to Neowin.

One of the biggest changes is the pivot categories for Bing. Previously, it gave Windows Phone 8 owners the choice to go to Web, Local, Media, or Shopping search results. Now the number of pivot categories has been reduced to just three and the labels themselves have been changed to Web, Images and Video. The Media label was expanded to Images and Video, while Local and Shopping were dumped completely.

The Image pivot now features large thumbnails of photos while the Video pivot has video previews in a 2x2 format. The Web search has also been changed to include more content such as local results and product cards for items.

It's possible that Microsoft started the update earlier than planned and thus did not have time to issue a more detailed press release or blog post about the changes, Neowin says.