Q. This year (5781-2021) when Erev Pesach is on Shabbat, does one read the Haggada then or is it better to read it on the prior Shabbat as the Shabbat Hagadol drasha is also preceded to Parshat Vayikra?
A. Mishna Berura (430: 2) maintains that although the Shabbos Hagadol Drosho is imparted on the prior Shabbos Vayikro, the Haggada is said on Shabbos Erev Pesach.
However, some Poskim disagree, since it will be recited a few hours later and it would take away its novelty especially from the young ones. Nitei Gavriel (Pesach 1: 5: 11).
Horav Shlomo Miller’s Shlit’a opinion is that one should follow his received traditions and if not known one should follow the Mishna Berura.
Rabbi A. Bartfeld as advised by Horav Shlomo Miller and Horav Aharon Miller Shlit’a