It's been a long while coming, and I lot have people have been asking for it. The compatibility breaking change list for Version 2.0 (Beta1) has now been published up on GotDotNet publicly. See the default page at http://www.gotdotnet.com/team/changeinfo/default.aspx for further details.
There is a lot of good information up on this page. First is a list of all the API's that were obsoleted in V2.0. Second is a list of known breaking changes that you might encounter when running or transitioning your apps from V1.1 to V2.0 that we worked on as a team. Third is a list of API Changes made between the two versions.
I hope this information is useful, don't hesitate to comment on what you feel we need more of, are missing, etc. Looking forward to some good feedback.