Transitional Input Tax Credit: migration of eligible CENVAT credits to the electronic ledger subject to prescribed conditions and documentation. Registered persons may migrate pre existing CENVAT credits into the electronic credit ledger in prescribed time and manner, subject to eligibility conditions: credits must be admissible under GST, requisite prior law returns must be filed, and credits relating to goods cleared under notified exemptions are disallowed. Special rules permit claiming unavailed capital goods credit, credits for inputs held in stock with invoice evidence issued within twelve months, alternative relief where invoices are unavailable, and prescribed calculation and distribution mechanisms.