Basically this pressure is created by tax department to get good name for their department. There is no last date as of now.
How can you fix last date when there is no law notified yet. GST drafts are still not made public (Latest), when department officers are not sure how GST will look, it is really a bad thing to block access of existing tax payers if migration is not done.
I will suggest you to migrate so that you will have smooth transitional period once GST is implemented and notified. But yes, there is no last date without GST law.
chatCommentsRightly said but its really sad that vat departments are blocking access, in Karnataka many dealers are not able to login to their VAT account due to this. - GST PayerThis is to pressurize dealers to migrate at faster pace so that future troubles can be avoided. - Pulkit SharmaBut is it valid from law point? How can someone block your access when there is no compulsion put by a law which is yet to be notified? - Pulkit SharmaDate is extended upto April 2017. Believe me they will keep extending till August 2017. I do not see GST coming before september. - GST Payer