Deposit requirement for filing appeals: conditional admission of appeals unless a portion of disputed duty or penalty is deposited beforehand. A new deposit requirement bars certain appeals unless the appellant deposits prescribed percentages of the disputed duty or, where only penalty is disputed, of the penalty; different rates apply by category of order, subject to an overall monetary ceiling, and excluding stay applications and appeals pending before the amending Act. 'Duty demanded' includes amounts determined under the duty-determination provision, erroneous Cenvat credit taken, and amounts payable under specified Cenvat Credit Rules.