Held: The entitlement of credit of eligible duties on the purchases made in the pre-GST regime as per the then existing CENVAT credit rules is a vested right and, therefore, it cannot be taken away by virtue of Rule 117 of the CGST Rules, 2017, with retrospective effect for failure to file the form GST Tran-1 within the due date. The provision for facility of credit is as good as the tax paid till the tax is adjusted and, therefore, the right to the credit had become absolute under the Central Excise Act and, therefore, the credit is indefeasible and the same cannot be taken away. The right to carry forward credit is a right or privilege, acquired and accrued under the repealed CEA, 1944 and it has been saved under Section 174(2) (c) of the CGST Act, 2017 and, therefore, it cannot be allowed to lapse under Rule 117 of the CGST, 2017, for failure to file declaration form GST Tran-1 within the due date. It is further declared that the due date contemplated under Rule 117 of the CGST Rules for the purposes of claiming transitional credit is procedural in nature and thus should not be construed as a mandatory provision.  ( SPLA No.  5758 to 5762 of 2019. Dt. 6th September, 2019