Recovery of arrears: inadmissible transitional input tax credit and past duties must be treated as central tax arrears and paid from electronic ledgers. Recoverable amounts arising from proceedings under the existing law, including wrongly availed or inadmissible transitional CENVAT credit, assessments, appeals or return revisions, shall be recovered as arrears of central tax under the CGST Act. Principal amounts are to be recorded in Part II of the Electronic Liability Register and discharged through the electronic credit ledger or electronic cash ledger; interest, penalty and late fee are to be paid from the electronic cash ledger and recorded likewise. Pre GST return filing and payment procedures for past periods remain available via legacy portals, and arrears from non GST registered assessees are to be recovered in cash under the existing law.