Regarding migration to new gst portal

Hi Experts,

Assessee is registered under CBEC and shall be surrendering his STC wef 01.04.2017, for the reason of receipts below norms.

My query is, whether assessee has to register under new GST portal in this case ?

Or he can continue to old ACES website, file the return for half year ending 31.03.2017 and surrender the certificate online in April.

Thanks,

Himanshu