lch wrote:If I do php --version i get 5.3.10
This is the version which is installed in your Linux Mint environment, obviously you have installed PHP as well as via Xampp as via Mint Installer.
Inside localhost/phpmyadmin the webhost part of php 5.6.8 but that is not true.
It is true, because if you call localhost/phpmyadmin via a browser, the Xampp Apache delivers the contents and this Apache calls the PHP Version from Xampp (which is installed in /opt/lampp):
But the drush Installer does not know, that there is a Xampp installation, it simply executes a "php --version" and this does not yield to Xampps PHP, but to the PHP from Linux Mint (which is in /usr/bin/php).
You should remove the Mint PHP installation (via Mint Installer) and after you should modify the login in your Linux, you should extend the PATH Variable to include the /opt/lampp/bin folder, where the Xampp executables are stored.