I'm not sure about this one, I've got some frozen breastmilk out of the freezer and the date on it is from December. I've defrosted it and it doesn't smell. I've tasted it and it tastes ok (well it tastes a bit of the BM bag).
How old is your baby? The recommendation is usually 6 months max in the deep freeze. If it was for a toddler I'd probably use it, but maybe not for a young baby. That's not advice, btw, just what I would do!