Input tax credit extension allows claiming FY2017 18 invoices after Sep 2018 return until March 2019 return deadline. Allows registered persons to claim input tax credit on invoices and related debit notes for FY2017-18 after the due date for the September 2018 return until the due date for the March 2019 return, provided the supplier uploaded details under section 37(1) by the March 2019 due date; also permits rectification of errors or omissions in section 37(1) details during the same extended period.