Transitional input tax credit migration under GST allows eligible VAT credits to be transferred to the electronic ledger with conditions. Registered persons, except those under the composition scheme, may transfer admissible VAT credits to the GST electronic credit ledger subject to prescribed conditions: carried-forward credits require prior returns for six months and conformity with GST admissibility; unsubstantiated Central Sales Tax claims are ineligible until substantiated and refundable under the existing law; unavailed capital goods credit is transferable if admissible under both regimes; credits on inputs held in stock are allowed where inputs are for taxable supplies, GST-eligible, evidenced by invoices issued within twelve months, with prescribed calculation methods and special provisions when invoices are unavailable.