Fallout: London devs will “downgrade” Fallout 4 to save their massive mod

After years of work, the third-party modders at Team Folon announced over the weekend that their long-awaited (and recently delayed) "DLC-sized" unofficial fan mod, Fallout: London, is now in "QA testing" and awaiting the "final green light" from release partner GOG. But that release will apparently need to make use of a "downgrader" to work around a recent Bethesda "next-gen" update that upended all of the team's modding efforts.

In December, Team Folon announced that its work on the Fallout: London mod would culminate in a planned April 23 release, lining up with England's widely celebrated St. George's Day. Then, just weeks before the planned launch, Bethesda announced that its own planned "next-gen" update for the 2015 game would be coming out on April 25, two days after Fallout: London's launch target.

"That has, for lack of a better term, screwed us over," Team Folon Project Manager Dean Carter said in an interview with the BBC shortly after Bethesda's upgrade announcement. In a separate video, Carter said that the next-gen update "requires many of our internal systems to be updated," since the content they created in the Fallout 4 Script Extender likely wouldn't work under the updated code. That turned out to be a valid concern, as the next-gen update did end up breaking many Fallout 4 mods and saves after its release.

"With the new update dropping just 48 hours later [than our planned launch], the last four years of our work stand to simply break," Carter said at the time. "We've had the release candidate ready to go, but we've had to put it down for the fixes we know it's going to need."

Moving back to move forward

To implement those needed fixes, Team Folon said in a social media update over the weekend that it would make use of a "downgrader" to undo Bethesda's mod-breaking updates. "At the 11th hour we've discovered that the next-gen, even after updates, isn't stable enough," Carter wrote on the Team Folon Discord. "Thus, we are now going out on the old version, thus the need for a downgrader."

Team Folon's release plans were further complicated when Bethesda released another game update on May 13 that disrupted their work. "The most annoying thing for us is having something. Then delaying to wait for the next gen 3rd party fixes. Then having another update. Then having it still not working," Carter wrote on Discord. "It's been an utter frustration and every setback requires the testing process to restart. Which is why we've decided to go with the downgrader route and when the 'next-gen' is sorted, update it for that."

Team Folon initially planned to release Fallout: London on Nexus Mods, but the files ended up too large to host on the popular mod distribution site. Luckily, GOG provided a "light at the end of the tunnel" for the mod's release, Carter said, and the platform is currently helping provide the final quality assurance to make sure that "Fallout: London and its installer [and downgrader] work on all supported machines."

"I think for us, and what distinguishes GOG from Steam, is that we're just a bunch of very enthusiastic guys,” a GOG spokesperson told TheGamer in a recent interview about distributing Fallout: London. "There was just a project that we wanted to support, and we're like, ‘Hey, guys, this is great. Let's do it, it's gonna be fun,' Preparing for this, we're already having tons of fun.”

While Team Folon hasn't announced a new release date for Fallout: London just yet, it sounds like GOG's quality-assurance check is now the final thing preventing the long-awaited launch. When anyone asks about the release date on the Team Folon Discord, they're greeted with a stock message: "As soon as we fix what the update breaks, it'll be out."