The Windows Live Agents team blog just updated announcing the release of the Windows Live Agents 5.1 SDK. This is also apparently the last version of the SDK and Microsoft will be discontinuing support for the product in Summer 2009. Here’s what the team have to say:

We are very pleased to announce that WLA 5.1 is here!

It is with a heavy heart that we have to announce WLA 5.1 is the last WLA release. We are retiring our product and this final version is better suited to take you through the summer of 2009 when official support ends.

You, our developers and partners, have provided great feedback about our product that we have incorporated into product features, many of which are part of 5.1 release. We would like to thank you for all your feedback and participation.

We will no longer accept new hosting requests. To review your current Agents, go to our Partner Hosting portal at http://developer.phi.agents.live.com . For tips on self-hosting, please refer to this article.

Please use http://agents.live.com to download SDK. This version of WLA provides a number of features that allow for better and more intuitive agents development experience. As always we highly recommend you read the release notes about all new features and use help documentation provided with SDK for any question on usage you might have.

We still encourage you to continue using our Forum site for communication with development community and WLA team.

The Windows Live Agents website has also been updated to the new Wave 3 look:

It is somewhat a surprise for us to see that Windows Live Agents development and support will be discontinued. We wonder what the strategic motive is behind this decision, or whether it’s simply to reallocate resources to much needed areas due to a lack of widespread interest.