Which Ariba CIG Add-on to download and what is the difference between ARBCI1 100 vs ARBCI2 100?

We are implementing Ariba integration from ECC using the Cloud Integration Gateway approach. In terms of installing the CIG add-on for ECC, we are not sure which one to use:

1. Choose A and do one of the following for using SAP Ariba Cloud Integration Gateway 1.0, add-on for SAP ERP and SAP S/4HANA:
* If you use SAP ERP, click ARIBA CLOUD INT SAP ERP 1.0 and then download one of the following:
* SAP Ariba Cloud Integration Gateway 1.0, add-on for SAP (ARBCI1 100) - Use for EHP0 to EHP8
* Ariba Cloud Integration for SAP ERP EHP4 to EHP8. V.1 (ARBCI2 100) - Use for EHP 4 to EHP8

The difference is not clear - and it appears both ARBCI1 100 vs ARBCI2 100 work as the CIG add-on. However, we want to integrate with Ariba purchasing, sourcing and contracts - so it looks like we may need to use ARBCI2 100 as per the note above. Can anyone let us know the difference? We have SAP ERP ECC 6 EHP7.

Thanks,

Jay