New smartphones running on the latest iteration of Windows Phone 8, Windows Phone 8.1, will reportedly be available from April.

According to recent reports, the development of Windows Phone 8.1 has been completed. But the update will not "Release to Manufacturers" (RTM) as there are a few minor bugs, for fixing which the team still needs to work.

This is expected to happen over the next couple of weeks before the final version is shipped to OEMs to push out on the new devices.

Besides, the final build of Windows Phone 8.1 is currently said to be available for Microsoft partners which is being tested for the devices.

According to the latest disclosure by Windows Phone Central, which, after speaking to multiple sources familiar with the matter, reports that the new smartphones powered by Windows Phone 8.1 will be available starting 23 April.

There is no official word so far but the upcoming Nokia Lumia 630 and Lumia 930 and Samsung's ATIV SE are likely to be the top contenders for running Windows Phone 8.1.

The Windows Phone 8.1 Developer Preview version is expected sometime in late April. Although, there is no word on a definite roll-out date, it is believed to be in its final stages.

The Developer Preview programme will allow those with a free App Studio account and the Developer Preview app to download and install the final build of Windows Phone 8.1 on their devices running Windows Phone 8, much ahead of the official roll-out.

As for the official Over-The-Air Windows phone 8.1, there is no information as to when the update will be released. This is because the official update for each individual smartphone depends on the particular firmware which needs to be developed and tested by the carrier.

Microsoft is expected to make an announcement about the Windows Phone 8.1 next week at the company's Build Developer Conference, 2014 in San Francisco.