A few weeks ago the EWS Java API was made open-source. Last week the EWS Managed API (.NET based) went open source. So now you can download the code and contribute to it. You can also directly report bugs on it. This is another of the wonderful changes which are happening at MS as it moves forward, evolving, breaking down the needed walls and doing what needs to be done to get us all to an even more of a "more happy" state.
Here is the release notice:
EWS Managed API for .NET is now open source
You can get the code here:
EWS Managed API on GitHub:
The current release of the EWS Managed API can downloaded here:
Microsoft Exchange Web Services Managed API 2.2
I'm looking forward to see how this API changes with future updates and releases. Now you can be part of that story.