if the default version is working for you then you should keep this file in place. If you notice an issue though after you go live you will should update the file to the new version. The issue is basically that the API calls are getting mixed up with the testing versus live server. When you go live you will need to ensure that you are not posting values to the sandbox, this newer updated page should fix this for you.
Please post back and let us know if you have any other troubles with this.