Taxpayer migration procedure allows provisional ID holders to complete GST registration through specified portal and mapping steps. Special procedure is prescribed for taxpayers who received only a Provisional Identification Number and did not complete migration under FORM GST REG-26, permitting them to apply for GSTIN by furnishing specified particulars to the jurisdictional nodal officer and then completing registration through FORM GST REG-01 on the common portal. After approval, the taxpayer receives an ARN, new GSTIN, and access token, which must be sent to GSTN for mapping of the new GSTIN to the old GSTIN, followed by first-time login with the old GSTIN for generation of the Registration Certificate. Such taxpayers are deemed registered from 1 July 2017.