An official Windows Phone blog in French says that the first substantial update for Windows Phone devices may not come until the end of the month, a week or two later than expected.

In February, Microsoft CEO Steve Ballmer said to expect the update, which will include cut-and-paste functionality and performance enhancements, in early March.

But the Wednesday blog post on the French site, spotted by the Mobiletechworld blog, said users should expect to be notified of the update in the second half of March.

Microsoft did not reply to a request for comment about the potential delay.

All About Microsoft's Mary Jo Foley cites unnamed sources who say the update is now scheduled for March 21.

The delay could be due to persistent problems Microsoft is having with its very first update, which was designed to improve the update process. It had to suspend sending out the update to Samsung phone users because it made some phones unusable. Once it resumed sending out the update, a new problem arose that prevented some Samsung customers from installing the update. It has since devised a workaround for that problem.

Microsoft is now being criticized for taking so long to deliver the update, especially since the only new functionality it will include is cut and paste, a feature many people expected in the initial release of the product. The company started selling the phones in North America in November.

Ballmer said to expect additional updates later in the year including the ability to multitask, a new HTML5 browser and access to SkyDrive, Microsoft's online document-sharing service.

Nancy Gohring covers mobile phones and cloud computing for The IDG News Service. Follow Nancy on Twitter at @idgnancy. Nancy's e-mail address is Nancy_Gohring@idg.com