I've installed PHP on Ubuntu14.04 as shown in this link. I currently have PHP 5.5.9 installed, but the current stable release is 5.5.12, is there any way to install current stable release on Ubuntu 14.04 ?
Although http://www.dev-metal.com/how-to-setup-latest-version-of-php-5-5-on-ubuntu-12-04-lts/ is for 12.04, the steps should be the same. It seems you may have to add a PPA to get the latest version. PHP.net shows 5.5.12 as the latest stable release with a 1st May 2014 date.
Have a look at this page for a super-easy way of upgrading PHP to the latest version on 14.04 - http://www.dev-metal.com/install-setup-php-5-6-ubuntu-14-04-lts/
In short, you need to add the PHP 5.6 package created by Ondřej Surý to spt-get, then update and install php5. I've just done this myself and had no problems.