Nan Ha optipro 3 for over 2 years old

Hi all, My daughter only drinks Nan HA series formula. Tried to switch her to normal optipro a few times but she hates it and will gag. Now that she's turning 2 years old, I tried to transition her to Nan optipro 4 (step 4 does not have the HA series.) She hates it and will only drink half a serving and cries for her normal formula milk. Can she continues drinking Nan Ha 3 after 2 years old?