I found some blog posts about this, but it's rather lack of descriptions on possible side effects. I could really use some detailed on these steps: How to add a repo that provides PHP 5.4 into yum Can this seamlessly replaces the current PHP version in CentOS? How can I switch back to the official repo when it supports PHP 5.4? (current 5.3.3 in my system) Will there be any potential to break PHP modules I currently using?