1. Install epel and remi repositories:

# wget http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
# wget http://rpms.famillecollet.com/enterprise/remi-release-6.rpm
# sudo rpm -Uvh remi-release-6*.rpm epel-release-6*.rpm

2. Enable remi repository:
In the [remi] section of the file, set the “enabled” option to 1.

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

3. Upgrade PHP with this command:

# yum install php

Installation of Other modules and extensions for php 5.4.x

# yum search imagick
# yum install php-pecl-imagick.x86_64

# yum search soap
# yum install php-soap.x86_64

# yum search git
# yum install git.x86_64

# yum search nodejs
# yum install nodejs.x86_64

# yum search python
# yum install python.x86_64

# reboot

# /etc/init.d/httpd restart

# yum search denyhosts
# yum install denyhosts

For more details regarding denyhosts read this post

Installation of ionCube for PHP 5.4 (optional)

1. Download ionCube: For x32:

# wget http://downloads2.ioncube.com/loader_downloads/ioncube_loaders_lin_x86.zip

For x64:

# wget http://downloads2.ioncube.com/loader_downloads/ioncube_loaders_lin_x86-64.zip

2. Unzip file.
3. Copy ioncube_loader_lin_5.4.so to PHP extensions folder:

# sudo cp ioncube/ioncube_loader_lin_5.4.so /usr/lib/php/modules/

4. Set SELinux attributes:

# sudo chcon -u system_u -t textrel_shlib_t /usr/lib/php/modules/ioncube_loader_lin_5.4.so

5. Switch on ionCube in PHP config:

# echo "zend_extension=/usr/lib/php/modules/ioncube_loader_lin_5.4.so" >> /etc/php.d/zend_extensions_psa.ini

6. Check functioning of ionCube:

# php -r 'phpinfo();' | grep -i ioncube

You can also test ionCube Loader by using the helper PHP script “loader-wizard.php” that’s included in the ionCube Loader archive.