1. Verify current version of PHP

Type in the following to see the current PHP version:

php -v

Should output something like:

PHP 5.3.3 (cli) (built: Jul 9 2015 17:39:00) 
Copyright (c) 1997-2010 The PHP Group
Zend Engine v2.3.0, Copyright (c) 1998-2010 Zend Technologies

Great, now we can move on!

2. Install the Remi and EPEL RPM repositories

If you haven’t already done so, install the Remi and EPEL repositories

cd /usr/local/src/

wget https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm && rpm -Uvh epel-release-latest-6.noarch.rpm

wget http://rpms.famillecollet.com/enterprise/remi-release-6.rpm && rpm -Uvh remi-release-6*.rpm

Enable the REMI repository globally:

vi /etc/yum.repos.d/remi.repo

Under the section that looks like [remi] make the following changes:

[remi]
name=Remi's RPM repository for Enterprise Linux 6 - $basearch
#baseurl=http://rpms.remirepo.net/enterprise/6/remi/$basearch/
mirrorlist=http://rpms.remirepo.net/enterprise/6/remi/mirror
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-remi

Also, under the section that looks like [remi-php56] make the following changes:

[remi-php56]
name=Remi's PHP 5.6 RPM repository for Enterprise Linux 6 - $basearch
#baseurl=http://rpms.remirepo.net/enterprise/6/php56/$basearch/
mirrorlist=http://rpms.remirepo.net/enterprise/6/php56/mirror
# WARNING: If you enable this repository, you must also enable "remi"
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-remi

Save file end exit.

3. Upgrade PHP 5.3 to PHP 5.6

Now we can upgrade PHP. Simply type in the following command:

yum -y upgrade php*

Once the update has completed, let’s verify that you have PHP 5.6 installed:

php -v

Should see output similar to the following:

PHP 5.6.14 (cli) (built: Sep 30 2015 14:07:43) 
Copyright (c) 1997-2015 The PHP Group
Zend Engine v2.6.0, Copyright (c) 1998-2015 Zend Technologies

Better to restart httpd service:

service httpd restart