Version 4.00 and 4.00 sp1 together

Hi, many customers have version 4.00. for a new customer I have to work with version 4.00 sp1 but requires to remove first the previous version. This means that all the customers must be upgraded first to version 4.00 sp1 ? I need only for this customer to work with version 4.00 sp1. How easy is to upgrade version 4.00 to 4.00 sp1 ? There are modifications to 700 objects in new version.

Hi, this link should help: regards Daniel