The B737's are staying and not for sale.
Recent quote from CEP Research :
Blue Dart, India's largest air express, courier and package distribution company, has extended its domestic network with the addition of two B757-200 freighters, 21 new routes and a new air hub. The DHL subsidiary is increasing its air capacity by 50% through the move.
The B757s will augment Blue Dart's freighter fleet of five B737 freighters, and will increase capacity from 166 to 250 tonnes per night to service growing demand. Blue Dart's charter capabilities within the country will also be fortified. The route network will be extended to 60 with the addition of 21 route connections to the existing 39. To further strengthen the air infrastructure, an aviation hub will be launched at Ahmedabad, and the Hyderabad outbound gateway will be connected.
One day you are the pigeon, the next the statue ...