Migration of provisional GST taxpayers: special registration procedure requires portal application, GSTN mapping, and first-time login for certificate. A special procedure allows taxpayers who received only a Provisional Identification Number to apply for GSTIN by submitting prescribed details to the jurisdictional nodal officer, applying on the common portal using FORM GST REG-01, receiving a new GSTIN and access token from GSTN, and furnishing the new GSTIN, token and ARN to GSTN so it can map the new GSTIN to the old PID; taxpayers must then perform a first-time login with the old PID to generate the registration certificate.