The thing is that "jutro" can be either an adverb or a noun. If it's a noun (similarly as "from Monday until Wednesday"), then it of course undergoes declension. "od" takes Genitive, and the Genitive form is "jutra".
I translated this as "from tomorrow through Wednesday" and got marked as wrong. In English, both "until Wednesday" and "through Wednesday" are treated the same (except maybe as to whether Wednesday is included in one nor the other).