Update current version.

README.md

@@ -45,7 +45,7 @@ cmake [-G generator] [-DBUILD_SHARED_LIBS=ON|OFF] ..
 
 # Recent Release #
 
-[yaml-cpp 0.5.2](https://github.com/jbeder/yaml-cpp/releases/tag/release-0.5.2) has been released! This is a bug fix release.
+[yaml-cpp 0.5.3](https://github.com/jbeder/yaml-cpp/releases/tag/release-0.5.3) has been released! This is a bug fix release. It also will be the last release that uses Boost; futures releases will require C++11 instead.
 
 [yaml-cpp 0.3.0](https://github.com/jbeder/yaml-cpp/releases/tag/release-0.3.0) is still available if you want the old API.