Hi Winston,
My name is Ryan and I am part of the Audience Manager Customer Care team at Adobe. Jantzen asked if I could hop in and help further answer the questions you have around the Visitor ID service changes he mentioned.
My understanding is that the calls you see will change depending on whether you are using the stand-alone Visitor ID service code (visitor.js), or if you have it implemented via the AppMeasurement code. If you are seeing the IBS call today, you will continue to see it but the DPID and the DPUUID values will be replaced by the CID and CID_IC values.
Regarding the Integration Code (IC), when added to the data source this functions in place of the DPID value in the http calls (when using the new variables). This will need to be added to the data source in question prior to making the change, and when the http calls are made it will directly point to the desired data source. Because of this, when you upload the data files, you can continue to do so using the same format you have been; continuing to utilize the DPID as the data target.
Hopefully this helps provide more context around the questions you are asking, but let me know if you have any other questions!
Thanks,
Ryan Hamilton