Boost 1.55.0
boost has been upgraded to version 1.55.0. This update brings a large number of bug fixes and enhancements, one new library (Predef), and a slight change in requirements as support for very old versions of several compilers has been removed. For a full list of changes, see the Boost 1.55.0 Release Notes.
GCC 4.9.x
The GNU Compiler Collection (GCC) has been upgraded to version 4.9.x, and all Fedora packages have been rebuilt with this new version of GCC.
The update provides a large number of bug fixes and enhancements. Among others, the C++11 support for regular expressions and partial support for C++14 has been added. In addition, the OpenMP 4.0 standard is now supported, as well as the Undefined Behavior Sanitizer (UBSAN).
For detailed information about all changes, see the GCC 4.9 Release Notes.