No, it depends on many factors and, I think, a wizard.
There's no telling what your date is going to be (mine is currently sitting at 16 months after my iPhone 4 purchase) but whatever it is, the question is 'did it change.'
For me, no, it has not. It's the same today as it was when I last checked 2 months ago.
No change here either. Obviously I pissed off the wizard.
(For the record, full upgrade is 3/2012, 18 months after purchase, single line with a hefty FAN discount--low minutes too, so monthly is under $80. I wasn't expecting a change and don't intend to upgrade with this release anyway.)