Extension of exemption under CGST Act by substituting the notification cut off date, deferring expiry of the prior tax position. Amends the Central Tax (Rate) notification to substitute the prior cut-off date at the end of June with a later end-of-September date, thereby extending the period during which the existing rate/exemption regime under the CGST framework continues to apply; the amendment is a temporal substitution of the operative date without changing rates or other substantive conditions.