en_tn/jer/45/01.md

this was in the fourth year of Jehoiakim son of Josiah

This information can be placed at the beginning of 45:1 as in the UDB.

in the fourth year of Jehoiakim

The words "of the rule" are understood. Alternate translation: "in the fourth year of the rule of Jehoiakim" (See: rc://en/ta/man/translate/figs-ellipsis)

fourth year

The word "fourth" is the ordinal form of the number four. (See: rc://en/ta/man/translate/translate-ordinal)

he said

"Jeremiah said to Baruch"