This is interesting because the phone is released in the US just today and T-Mobile is already pushing some updates. The change log indicates the update fixed many bugs, improved performance and stability. Also Samsung indicated there are some features are also updated.
As we posted earlier many T-Mobile subscriber got Galaxy Note 4, three days before the actual release date, i.e 17th October.
The update is over the air update. So do not forget to update once you get your phone.