Your IPA is not reviewed annually. If you have only received a cost of living increase you do not have to advise of the increase. However, if you have received substantially more they you should let them know so they can review.
I had a 3.5% pay rise that I didn't think to notify the OR about. I told them about last year's, which was before I was discharged and they weren't interested, and this years was less - despite the cost of living going up!
Tomorrow is a mystery, yesterday is history, today is the present, a gift to make the most of.