Microsoft announced its updated Windows Phone 8 developer proposition, including the long-awaited general availability for its SDK, and a “refreshed” Dev Center portal which is now open for app submissions.

The company said that it is “delivering close alignment with Windows 8 via a common core”, but this has meant that “every major underlying subsystem had to change”.

However, the benefit is that it “allows developers to take advantage of support for native C++ programming, familiar tools, and common APIs to target phones, PCs and tablets for an estimated combined opportunity of roughly 500 million units next year”.

The SDK is based on Visual Studio 2012, and will enable developers to create new Windows Phone 8 apps, as well as creating and upgrading existing WP7 apps. Apps written for the earlier version of the OS will run on the latest incarnation, but not vice-versa.

In a blog post, Microsoft said that “more than 90 percent” of the items requested by developers have been added, such as native code, in-app purchases, and easier reuse and porting.

It also highlighted a number of newly added features, such as Live Tiles and NFC support.

One area where the company has seen some criticism is in the supported platforms for the SDK: developers need a PC running Windows 8, a platform which was only commercially released recently.

As an introductory offer, developers have until mid-next week to register for a Dev Center account for the reduced free of US$8, compared with the regular US$99 charge.