Is there any easy way to change code from PHP4 to PHP5? If i have a script in PHP4 is there any easy way to change it to PHP5 or is only hand code that is possible?
You don't need to convert the code. Just use it with php5. There is difference between php4 and php5 only in some functions - mostly in the object functions. You will see the errors if php5 don't supports the functions in your code and then you should find a way to replace them with the new functions. Good luck!
I've seen some auto app that change php4 codes to php5 codes but I don't think they'll work. Best thing to do is to modify your codes from php4 to php5 on local machine and upload the php5 codes to server when you're ready so you can still have an online website while developers work on the migration. I currently use php4 on one of my site, and switching to php5 can take me a month to review all codes. I won't switch the version unless I really need the functions on new version.
That's a good thing that your server stopped supporting PHP 4, you can fix the errors one at a time or have someone else to do it for you, or you can post the errors you get on DP forums.