A Microsoft employee this week accidentally blogged about an upgrade to Office Mobile that shouldn't be available for another couple of weeks.

The upgrade, when it becomes available, should solve an incompatibility issue that left Windows Mobile 6.0 users unable to read Office 2007 file formats.

Jason Langridge, who works in Microsoft's Windows Mobile group in the U.K., wrote that Office Mobile 6.1 was available and he included a link to the download page. But a representative with Microsoft's external public relations firm said that the upgrade was put up on the site initially for internal testing and was accidentally made available to the public.

The new version of Office Mobile is expected to become available very soon, probably within the next two weeks, he said.

Langridge has not yet removed the post from his blog.

The download page, which is no longer accessible, said that the upgrade allows viewing and editing of Word documents and Excel Workbooks and viewing of PowerPoint slides that were created using Office 2007. Office 2007 was released in January and is based on the Open XML format. Windows Mobile 6.0 devices began hitting the market in the middle of this year but users have been unable to read Office 2007 documents, unless they used a third party software product. DataViz, for example, offers software that lets Windows Mobile 6.0 users read Office 2007 documents.

Users of the upgrade will also be able to view and extract files from compressed .zip folders, it said.

Following the link on Langridge's site now leads to a page with this message: "The download you requested is unavailable. If you continue to see this message when trying to access this download, go to the "Search for a Download" area on the Download Center home page."