I'm planning a project to upgrade internally-developed app from SQL Server 2005 to SQL Server 2012. I hope to use Service Broker as a bridge while in transition. Are there any issues to consider in a forward-compatibility scenario like this other than newer features like multicasting not being present? I can't find anything in BOL specifically about compatibility.
The answer is yes, you can do cross SQL Server versions service broker as long as all instances are 2005 or newer, and only one of the instances can be SQL Server Express Edition.