The following precautions are to taken for carry forward of existing duties/taxes under GST :-
1) Input/Input Services/Capital goods received, however the same has not been recorded in books of accounts or recorded in books of accounts but not considered in ER-1, Carry forward of same in GST regime is not allowed. Thus availed and record all the eligible cenvat credit in ER-1.
2) Carry forward of Cenvat credit and ITC credit in GST regime very carefully, if registered person has wrongly enjoyed/carry forward the credit in GST portal, the same will be recovered as arrear of tax under GST.
