I was working on maintaining SQL Server DB backups on a new server of mine, but I faced an error message that telling me my backup file created on database engine 10.50.4042 version while my current database engine version is 10.00.5500. I believe you already faced such an error message.
Once I got that error message, the first question came into my mind is how can I know what these version numbers really menas to me and how can fix this issue.. answering to these question was nicely listed into this blog post, actually the author of this blog did a great job of creating a catalog of versioning numbers and what each one means. https://buildnumbers.wordpress.com/sqlserver/