Microsoft has released the software development kit for Windows Phone 7.8, and the company is expected to roll out the update to users at the end of January.
Microsoft's Colombian Facebook page was first to announce Windows Phone 7.8 would arrive January 31, with a rollout through the first quarter because carriers have to verify the software. UK wireless carrier O2 corroborated the date on Twitter in reply to a user question, saying that the "update will be released by the end of January and will be available via Zune."
Many existing Windows Phone 7 and 7.5 users expect the 7.8 software update. The latest version of the OS, Windows Phone 8, was launched in October, but only comes with new devices from Nokia and HTC, such as the Lumia 920 and 820 or the Windows Phone 8X and 8S by HTC.
Windows Phone 7.8 is meant to be a bridge version for older Windows Phone devices, such as the Lumia 610, 710 and 800. The update will give users access to the resizable live tiles from Windows Phone 8. Users will be able to choose from three sizes of tiles on the home screen. Other minor updates include Bluetooth file transfer, new theme and accent colors and a new lock screen option to automatically display the Bing picture of the day.
There will be still a bunch of important features from Windows Phone 8 that won't make it into the 7.8 update, according to a previously leaked document. Windows Phone 7.8 won't include real multitasking, support for MicroSD cards, secure boot and encryption or over-the-air updates.
It's still not clear why Microsoft delayed the rollout of Windows Phone 7.8. When Windows Phone 8 was launched, the company was meant to follow up with 7.8 for older device shortly afterward. Even if Microsoft's 7.8 update arrives on January 31, it could take weeks to trickle down through carrier filters, especially in the U.S., where AT&T or Verizon have been keeping mum about the upgrade.