Jurisdiction in GST petitions: central commissionerates retain authority to continue proceedings and file appeals when taxpayers fall under state control. Central GST commissionerates retain residual authority to continue defence and pursue remedial judicial measures in GST petitions before High Courts even when taxpayers are assigned to State jurisdiction. Coordination between Central and State GST officials is advised when filing appeals to avoid divergent positions. The Board has been processing appellate proposals, notably on TRAN-1, and has urged States/UTs to take protective steps against adverse High Court orders. Omitting the Union or revenue departments as respondents when central law is challenged raises Principles of Natural Justice concerns; an addendum to Master Instruction mandates obtaining CBIC policy comments and central-state coordination for effective defence.