Is it possible to get Bluetooth Smart 4.0 onto an iPhone 4?

Or is that a hardware issue?

Here's the thing. I've got an un-jailbroken iPhone 4, which doesn't have BT 4.0, which I am now considering jailbreaking if it's possible to get BT Smart 4.0 onto to this phone.

Phone specs:

Version - 7.1.2 (11D257)
Carrier - AT&T 16.0 (locked)
Model - MD127LL/A
Modem Firmware - 04.12.09