Mango, the latest version of the Windows Phone mobile operating system, was released to manufacturers Tuesday, Microsoft said.

The OS code was officially turned over to manufacturers and mobile operators. The OS will come pre-installed in new Windows Phones and will be available as an update to current Windows Phone handsets in the fall, said Terry Myerson, Microsoft's vice president, Windows Phone Engineering.

In May, Microsoft said Mango will bring 500 improvements to the mobile OS. Analysts were concerned that the company didn't show new smartphones that would run the update.

First Windows Mango Phone unveiled (Video)

Myerson said Mango will provide a "smarter and easier approach to communications and apps" and mentioned an email "conversation view" that makes long email discussions more efficient. A feature called "threads" will bring together text, IM and Facebook chat into one conversation, he added. Mango also includes Internet Explorer 9 for faster web browsing.

Microsoft and its fans have high hopes that Mango will boost sales of smartphones using the Windows Phone OS, which ranks fifth overall among mobile OSes globally.

Microsoft CEO Steve Ballmer admitted in July at its partners conference that the current version, Windows Phone 7, hasn't done well. "We've gone from very small to... very small."

But Ballmer also took the long view, saying, "you will see a lot of progress in the market going forward."