(covers information from several alternate timelines)
In one possible timeline a generation prior to 2374, the Zahl defeated the Krenim Imperium, despite the temporal science they used to construct advanced weapons. They disbanded the Krenim fleet and retook the territories they had annexed.
In 2374, two Zahl starships greeted the USS Voyager upon its arrival in their space. During the meeting, the entire Zahl civilization was erased from history by Annorax's weapon ship. The erasure of the Zahl achieved an unprecedented 98% Krenim restoration, although the Krenim colony on Kyana Prime was not restored. When the weapon ship was destroyed, this timeline was negated. (VOY: "Year of Hell")
In the novel A Pocket Full of Lies, the crew of Voyager and the Full Circle Fleet (β) investigated disputed space of the Zahl and the Rilnar following the discovery of the survival of the alternate Kathryn Janeway encountered by Chakotay during the incident in "Shattered" in which the USS Voyager was shattered into 37 different timeframes.