You can find out which PHP version is defined by default by clicking on [Webhosting] in the easyname Controlpanel and then on [PHP Settings]. At the very top you will find the set version, followed by a list of available versions, now click next to the desired one on "Set as default" to change the setting. Under the link "Settings" next to the respective version you can adjust some parameters, eg. the PHP session_cache from filesystem to redis or vice versa.
If you only want to customize the PHP version for a specific subdomain, which may happen, for example, if a Content Management System requires a specific version or is incompatible with a newer one or the like, please do the following:
Log in to your easyname control panel. Then click [Domains] followed by the [Subdomains] link in the Availability column next to the affected domain. Then click on the notepad icon next to the subdomain to customize the display options. When selecting "Show webspace content" you will find the link "Settings" next to the text field for the folder, click on it to specify the PHP version and if necessary make further settings (eg register globals on / off with PHP 5.3 ).
If the PHP version of a subdomain differs from the set standard version, it can be found in the control panel under [Webhosting] and then on [PHP Settings] at the very bottom of the page. In the left column is the respective subdomain, in the right the corresponding PHP version.