The "incompatibility message" in the plugin manager of the Community Builder 2 component has been solved some months ago and should be fixed when "cb2_*" plugins are used that are part of each uddeIM package.
UddeIM is basically a Joomla component and I always check if it is compatible to the current version of Joomla. When a 3rd party component (like CB) changes its API there might be incompatibilities or cosmetic issues (like the "incompatibility message" that was because of a changed XML format) for the corresponding CB plugins but that does not mean that uddeIM is incompatible in any way. uddeIM runs without CB, so you could also claim that CB is not longer compatible to uddeIM.
UddeIM is one of the oldest components that is available for the Joomla platform. It still runs on Mambo 4.x and Joomla 1.0 up to the current Joomla version. So I think uddeIM is one of the best supported components.
When you are of the opinion that uddeIM is not a viable component, please feel free to choose a different component that fulfills your needs. I am pretty sure that there are other components that do not show incompatibility warnings in Community Builders' plugin manager.