The idea of the afterword came during the OpenSER summit. I was talking with a friend who told me about the new configuration file for OpenSER 1.3. It is a bit different than the one available for 1.2. Verifying the information, I found that the 1.2.3 was different too. So I decided to present here some of the best improvements seen in the new default files; basically the CANCEL handling (already integrated in the current script) and the method filtering in the lookup() function. RTPproxy is another missing part in the book. I have chosen MediaProxy, but now I have heard from some people that RTPproxy is in some cases 10 times faster than MediaProxy. Finally, I will describe some areas for improvement and further investigation.