Take Notice of Exchange Web Service Notifications
The Exchange API-spotting blog, which is run by the Exchange MSDN content and Exchange API product folks, as a new post about the transition from store event sinks to Exchange Web Service notifications. The aim is to provide some more detail about notifications and try to directly answer some questions that have been posed by developers about how notifications can realistically replace store event sinks when they go away.
...If you have feedback for the product team about the transition or any scenarios that you are concerned about, please comment on their blog post. These posts are going up well before the next release of Exchange in order to keep you informed but also to hear what you have to say. The nice thing about Exchange 2007 is that you have EWS notifications already available to test with so while your store sinks might work now, you should begin thinking about and testing the migration of your sink solution to one based on EWS notifications. If you hit roadblocks now my team can work with you on Exchange 2007 and get answers before the upcoming release where Exchange store sinks are not a fallback option...
In fact, the Exchange MSDN content team has been very busy spreading the word about what the transition from the gang of de-emphasized APIs (CDO 1.21, CDOEX, WebDAV, etc.) to the new ones (EWS and Agents) will look like...
Migrating from Exchange 2007 Legacy APIs