[TYPO3-english] what are the reasons to upgrade from PHP5.2 to newer ?

[Chai name]

Hello  

our customer is worried about upgrading their own system specifications as it may effect whatever is  already running on the server

so

 - What are the potential risks for them to  upgrade ?    backward compatibility  or ..... your opinion......?


it will be great if you can show me the example , especially to describe for non-technical IT user to understand this

thanks