We know many folks are looking forward to RTM. Developers currently working on apps in the Store are especially excited. We have hundreds of apps in the Windows Store now and many more on the way. There’s a broad set of developers around the world that we have been working closely with since the first Developer Preview. The WinRT platform is evolving rapidly during development based on feedback, and we have the dual task of keeping the Store up and running so we can supply apps to the millions of Preview users, while also getting ready for the next build. It means that if we change or add APIs or improve the tools, the apps will change and require an updated OS to test and verify the app. That’s why we have been providing updated builds to developers who have or are committed to having apps in the Store through strong partnerships. 

This post explains the work we’ve been doing since September to keep developers updated with APIs and tools so that apps can stay up to date. We’re doing this even after the Release Preview, just to make sure new apps are ready to go once we get to broad availability. This post was authored by Dennis Flanagan, who leads our ecosystem outreach team.  --Steven


As we approach the release of Windows 8, the catalog of Metro style apps continues to grow. To date, people have experienced apps that Microsoft has included with the downloaded build, and those that are offered in the Store in both the Consumer Preview and Release Preview timeframe. Many of those apps are great examples of immersive, touch-first Metro style experiences. However, like the Windows releases they run on, these apps are preview versions of the apps to come. The final versions of all Metro style apps will be available when Windows 8 becomes generally available.

Last year, we began working closely with the developer community by releasing early versions of the Windows 8 platform and tools. We decided to engage developers earlier in the engineering process so we could help them build skills in Metro style app development and give them the opportunity to influence the platform through feedback. Since September of 2011 we have released 8 developer preview versions. Some of these versions have been available to a limited developer audience. Some have been distributed broadly. All of these releases had similar goals:

  • Deliver new capabilities and APIs
  • Update tools to simplify Metro style app development
  • Enhance performance and reliability
  • Respond to developer feedback

We released our first Developer Preview version at the //build conference in Anaheim. This version introduced developers to the Windows 8 platform, tools and programming models. The WinRT platform included new APIs, and we used the conference to present literally hundreds of technical sessions and samples to give developers a basic understanding of the platform. . Many developers got right to work building Metro style apps, produced some impressive early results, and provided us with useful feedback and recommendations about how to improve the platform and tools.

We made it clear that the first Developer Preview ("DP1") was an early version of the code, and we had a lot of work to complete Windows 8. DP4 and DP5, released in January and February of this year, were targeted at developers who wanted to be the first to publish applications in the Windows Store. By the time we released the Consumer Preview in February of 2012, we had added almost a thousand new WinRT APIs, and had modified hundreds of other APIs based on developer feedback.

For a detailed description of the changes that happened between //build and Consumer Preview, check out these posts on our App Developer blog:

In April and May of this year, we released DP6 and DP7, which allowed developers to prepare their apps for the Release Preview. However, in close collaboration with the development community, we've continued to evolve the platform in response to their feedback. By the time we delivered the Release Preview, we had added 334 more APIs and continued to change existing APIs to address feedback.

One example of a change we made in Release Preview (RP) based on developer feedback is the HTML ListView control (in WinJS). This was an area where lots of developers had difficulties, so we overhauled it to make it easier to work with and to allow a much more extensive degree of performance tuning.

We also made lots of improvements to developer resources, such as templates in Visual Studio. We even added a new template that makes it easier for developers to start a new project and get a great app up and running in very little time.

Design tools were another focus area for improvements. Metro is a design-forward experience, which means the app’s user interface is one of the key ways developers get their apps noticed and differentiate them. We did a lot of work to make it as easy as possible for developers to integrate all the new Metro style design concepts into their apps.

For a complete overview of the changes between CP and RP, see What's changed for app developers since the Consumer Preview.

Our next major milestone is the release to manufacturing (RTM). When the code reaches this milestone, the platform is complete for general availability (GA), and so we won’t have interim updates for developers.

When Developers get the RTM version, they will continue enhancing the features, capabilities and performance of their apps. Some of the apps you’ve already seen will look and perform differently when you download the final released version. There are also many more apps in development that haven’t been released to the Store yet. Many of those developers are waiting for RTM to put the finishing touches on their apps.

The release of Windows 8 will be a great milestone for app developers, but it is really just the beginning. A great benefit of the built-in Windows Store and update mechanism is that they provide developers with the opportunity to gain wide distribution for new apps and continuously improve apps that they've already released. As the app developer community evolves, we expect app developers to take advantage of this and provide regular updates to apps.

--Dennis