CDHDR content lost after upgrade
After upgrade from 4.7 to ECC 6.0 and completing SPDD and SPAU, we realized that old CDHDR data missing. CDHDR content now only have change document after upgrade. I've check SPDD and SPAU and CDHDR is not included in here but it is included in SE95 list because there is new custom index that was created long time ago in 4.7 system.
Is this the cause of the deletion? If it is, what should we do to prevent the lost of Change Document data in upgrade process?
Thanks in advance for the response.