Complex sentence: The GSLV MK-1 had a Russian-made cryogenic third stage, this has been replaced with an Indian-built cryogenic stage for the GSLV MK-2.
Split into simpler sentences: The GSLV MK-1 had a Russian-made cryogenic third stage. This has been replaced with an Indian-built cryogenic stage for the GSLV MK-2.