Special GST payment procedure allows quarterly filers to deposit an advance portion of tax liability during early quarter months. Notification permits quarterly filers or persons filing for parts of a quarter to, in the first and/or second month of a quarter, deposit into the electronic cash ledger an amount based on the tax debited in the preceding return period (preceding quarter for quarterly filers; last month of preceding quarter for monthly filers). Exemptions apply where ledger balances are adequate or liability is nil, and eligibility requires filing the return for a complete preceding tax period.