It is the method to differentiate the old build and the new build after changes made to the existing code. For the old code v001 and next time u have to increase the version number as v002 like that. In my last company we haven't use any version controlling. We just delete the old build and replace with the new code.
We don't maintain version controlling in informatica. We are maintaining the code in VSS (Virtual visual Source) that is the software with maintain the code with versioning. Whenever client made change request came once the production starts we have to create another build.