An early look at Firefox OS's upcoming looks and features (pictures)

Mozilla showed off a preview of the new version of its Firefox OS mobile operating system at Mobile World Congress in Barcelona, Spain. One big change is in switching among tasks, where you can slide your finger in from the left or right edge of the screen to leaf through the apps like pages.

One of the biggest changes coming to Firefox OS in the next year will be a unified search mechanism that leads users to content on the phone, on the Web, or to the Web-based applications Firefox OS runs. It starts off as a small label at the top of the screen showing what app is running or Web page is open.

When you pull down a little bit from the top of the universal search bar, it expands into a more spacious view into which you can type search queries. Pulling down even farther invokes a status bar -- not the Android-like notification bar in today's Firefox OS.

Firefox OS will predict what letter you're likely to type next and make the tap target for that letter larger -- invisibly -- to try to improve typing accuracy.

The notifications screen now is reached by dragging up from the bottom of the screen.

A long-distance pull down from the top of the screen shows tasks if you want to switch from one app to another. It can also be reached with a long press on the home button, a feature in today's Firefox OS.

Firefox OS will get a more spacious layout, and icons shift away from pictures and toward illustrations instead.

The top of the new user interface tells you what app you're using. You can tap on the text to change to a new app or to search.

Firefox OS 1.3, though not as radical a change in interface functioning, is due in a few weeks.