GST ON WORKS CONTRACT

Saiman Dutta (20 Points)

29 October 2017  
A promoter has started construction of residential apartment before 1.7.2017 and all flats have been booked before 1.7.2017 also 99% construction has been done before1.7.2017. Now in the month of November, 2017 the promoter will receive the balance amount from the customers and transfer the flats to customers.
Is GST applicable in this case? explain in details plz.