I had to recently update PHP 5.3 on my CodeAnywhere DevBox to PHP 5.4.32. The operating system running on CodeAnywhere DevBox instances is Centos 6.5. and it uses yum package manager.
These are the exact commands I ran on the DevBox
sudo rpm -Uvh http://download.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm sudo rpm -Uvh http://rpms.famillecollet.com/enterprise/remi-release-6.rpm sudo yum --enablerepo=remi,remi-test install httpd php php-common sudo yum --enablerepo=remi,remi-test install php-pecl-apc php-cli php-pear php-pdo php-mysql php-pgsql php-pecl-mongo php-sqlite php-pecl-memcache php-pecl-memcached php-gd php-mbstring php-mcrypt php-xml
After this, it's done!
You could simply create a php file and run phpinfo() to check the version.