The full release notes for RC 2 are (only) at the sourceforge link you listed, there are a few notable additions like transaction malleability handling + new default minrelaytxfee



Linux build exhibits the same issue that my own test build has, namely that the executables are not (executable) from the Linux GUI (tested on Mate and Xfce). Executable permissions + properties are all as they should be, and the files are interpreted by the GUI as file type "Shared Library", not "binary" or "executable". Works fine if you launch from command line.