Microsoft gave the world a glimpse of Windows 10 running on its smartphones last month, but the company has not yet released its first public preview of the new OS, which will replace the standalone Windows Phone operating system. Microsoft promised that it would deliver the first preview in February, but it has not yet committed to a firm date.

But the company is now seeding a build of Windows 10 for phones to a select group of around one thousand testers in various departments across the company. This is believed to be a final round of internal testing to resolve any last niggling bugs before the preview is made publicly available.

Neowin has learned that a build named 'Windows 10 Technical Preview for phones (8.15.12492.41)" is now available to these testers. Note that the OS version number has increased from 8.10 in Windows Phone 8.1, up to 8.15 in the Windows 10 preview, but it is not clear if this build 12492 will be exactly the same version as that which is released publicly this month.

One amusing touch in the update process for the new build can be found on the familiar 'Update successful' screen, which displays when everything is complete. Alongside the build number, it displays a quote from Seattle Seahawks quarterback Russell Wilson; a phrase that he uttered after the team lost the Super Bowl to the New England Patriots on Sunday:

Every setback has a major comeback.

Microsoft has of course suffered many setbacks in its efforts to grab a meaningful chunk of the smartphone market, but after more than four years of trying, its share of the market remains below 3%. The company will no doubt be hoping that after so many setbacks in the past, its big comeback in the mobile space can soon begin with Windows 10.