Users of Windows Phone 7-based phones will have to wait until the new year for the long-promised version 7.8 updates to the obsolete operating system.
The update is intended to improve customisation and mimic the features and functions of Windows Phone 8, which replaced Windows Phone 7.
However, while Windows Phone 8 was launched in October, users of Microsoft's old operating system have been left waiting for the update, despite a promise to release the update after the launch.
Earlier this week, some Windows Phone 7 devices were reportedly receiving the long-awaited updates, but these were only for "pre-production and early non-branded devices", according to Nokia.
Instead, the update will be streamed to users early in the new year.
Windows Phone 7, which was only released in November 2010, is based on the Windows CE code base, which was originally developed in mid-1990 for handheld computers.
Windows Phone 8 is based on the Windows NT kernel, the same as the Windows 8 desktop operating system.