As of SAP Net Weaver 7.0, a new object concept is available for Data Sources (object type R3TR ISFS), which up until now were called Data Source replicates in the BW system in the case of SAP source systems. This new object concept is used together with the modified object concepts in the data flow and the process design (transformation, Info Package for loading into the PSA, data transfer processes for distributing data within BW). The object type for a Data Source from the new concept - subsequently called Data Source - is R3TR RSDS.
If your dataflow is modeled using objects that are based on the old concept (3.x Info Sources, 3.x transfer rules, 3.x update rules) and the process design is built on these objects, you can continue to work with 3.x Data Sources when transferring data into BW from a source system.
More information:Data Source
General Practices with Emulation and Migration