R' Yitzchok Stern (Strimtura) - From where is there a record of death as February 11, 1848 for R' Yitzchok Stern

Agadot Strimtura by Shmaya Avni, page 19, gives 1845. Matzevet Kodesh gives 1845 at age 82.
The Yihus Mishpahat Stern, attached to this profile gives ז אדר תר"ח, which is 1848. That is where the listed date comes from. Somebody may have mixed a heh and a Chet. It is hard to know what is the correct information.