I won't lose any data or have any problems with the current 5.5 php databses that I have. Here is the part that concerned me from the above article (thankyou);
Warning: If you upgrade from PHP 5.2 or 5.3 to PHP 5.4 or 5.6, you will no longer have access to those older versions of PHP. If you are currently using PHP 5.2 or 5.3, make sure your site is compatible with either PHP 5.4 or 5.6 before changing your PHP version.
Before changing the version make sure WordPress and any add-ons are up-to-date. It is also important to check each theme and plugin you use for compatibility issues, delete any that are no longer compatible beforehand.