Hike in Interest Rates & Deposit Rates

As all of us know there has been hike in the interest rates & deposit rates by various banks recently. Increased interest rates are applicable to all borrowers i.e. those who have availed the loan & those who will avail it after the increase. However, my question is : Is the increase in deposit rates applicable to existing Fixed Deposit holders or not? In other words, do existing FD holders continue to receive interest mentioned in their FDR or at the increased rate?