GST migration of service tax registration after Aug 2016 from 1st feb 2017 to 20th March 2017: 

GST migration of service tax registration after Aug 2016 will start from 1st February 2017. Registration for the same will close on 20th March 2017. This same provision will also apply on Excise and VAT registrations after August 2016.  It is important to know that the GST migration for taxpayers registered before Aug 2016 will start from 9th January 2017. There will still be the taxpayers who will take registration in service tax after March 20, 2017. They will also be allowed to migrate later on.

Which services tax registered person is required to migrate to GST: 

Service tax registered person who are not already migrated for having a VAT registration will be migrated here.