A free update has remastered an entire DLC from the first Vermintide and released it (again, for free) for every Warhammer: Vermintide 2 owner to enjoy. The three remastered levels are Karak Azgaraz, a dwarven fortress under siege and occupation by villainous Skaven rat-men.
The three classic Vermintide adventures are updated to fit in with Vermintide 2's mechanics, including challenges and rewards for the game. That means there are new challenges from cousin Okri to be overcome, lest you become complacent. There are also paintings for your keep and portrait frames to be won.
"In Karak Azgaraz, you and your party are sent to Khazid Kro to help a struggling dwarf war party sabotage the Skaven army. Traverse through the Dwarfen stronghold and turn the tide in your favor to successfully counterattack and foil the Pactsworn’s devious plans!," says the official description.
I actually remember these maps really fondly, as there was a great route through one of them where you could always get ammo at good intervals and therefore always be shooting those witch hunter pistols (and then throwing them aside with casual disregard.) The finest way to live in Vermintide, if I do say so myself.
The Vermintide 2 5.0 update accompanies this release. There are a few tweaks and bugfixes in there. There's also a new setting for Weapon Trail VFX, so you can turn those off if you hate them. The update That's alongside a release of some premium cosmetic hats for purchase if hat-collecting is your thing.