Microsoft unveiled an upgrade for its Office Mobile suite which contains Word Mobile, Excel Mobile, and PowerPoint Mobile applications.

The new file format used by Office 2007, the latest office suite launched by Microsoft in January this year is based on Open XML and until now the Office Mobile application weren’t compatible with docx (Word), pptx (PowerPoint), and xlsx (Excel) documents.

According to Microsoft the new file formats reduce file size, improve security and reliability, and enhance integration with external sources.

Also, beside the compatibility with MS Office 2007, the new upgrade adds enhanced viewing experience for charts in Excel Mobile, ability to view SmartArt in PowerPoint Mobile and ability to view and extract files from compressed (.zip) folders.

In October this year Jason Langridge, a Microsoft employee of the the U.K. office of Microsoft's Windows Mobile unit, has accidentally revealed the update of Office Mobile and he even provided on his blog a download link.
Microsoft said that the update was just an internal test version and the link was promptly removed.

The official upgrade is available here.