Advisory on Case Sensitivity in IRN Generation: This is to inform that, effective 1st June 2025, the IRP (Invoice Reporting Portal) would treat invoice/document numbers as case-insensitive for the purpose of IRN generation. The invoice numbers reported in any format (e.g. abc, ABC or Abc ) would be automatically converted to uppercase before IRN generation. This change aligns with the treatment of invoice numbers in GSTR-1, which already treats them as case-insensitive. (GSTN Advisory Dated 04/04/2025)