autoconf is a development tool used to generate automatically a platform-dependent configure script for compiling and installing software on UNIX/Linux platforms. autoconf is typically used with automake and libtool to minimize the efforts to build and package software for a target architecture.
To upgrade the default autoconf on CentOS, you can build the latest autoconf from its source. Here is the instruction on building and installing autoconf from its source.
$ wget http://ftp.gnu.org/gnu/autoconf/autoconf-2.69.tar.gz
$ tar xvfvz autoconf-2.69.tar.gz
$ cd autoconf-2.69
$ sudo make install
After installation, verify autoconf version:
$ autoconf –version