Like in Cent OS 5.3 you cannot update PHP version above 5.1.x.I have been using different repositories to update PHP to latest version but most of them break rpm one or two, which may let to unstable Server.Atomic Rocket Turtle ( company i found that regularly updating applications used in Cent OS/Fedora/RHEL.You will be seeing that i will be updating PHP from version 5.1.x to 5.2.12, which is latest till this date.You may like to read more about DNF here: The latest stable release of DNF is 1.0 (at the time of writing of post) which was released on May 11, 2015.It (and all previous version of DNF) is mostly written in Python and is released under GPL v2 License.In this howto i will describe how to update PHP rpms on servers to latest version.
Fedora contains software distributed under a free and open-source license and aims to be on the leading edge of such technologies.
DNF does Package Management using RPM, libsolv and hawkey library.
Though it does not come per-installed in Cent OS and RHEL 7 you can yum, dnf and use it alongside the yum.
It was first introduced in Fedora 18 and it has replaced YUM utility in recent release of Fedora 22.
DNF aims at improving the bottlenecks of YUM viz., Performance, Memory Usages, Dependency Resolution, Speed and lots of other factors.