October 2024 split Factorio in two: 2.0 rebuilt core systems and Space Age built a new game on top, while the 1.1 era — final form 1.1.110 — kept custody of the old world's giants. The megamods that defined a Factorio generation lived on 1.1, most famously Space Exploration, whose multi-hundred-hour campaigns didn't move on the expansion's schedule; whole communities and their saves stayed behind with them, deliberately. Add multiplayer's exact-version matching and the megabase factor — saves representing years of optimization — and "which Factorio" became a permanent question. The good news is that this developer answered it more thoroughly than anyone in this series.
01The DLC trap — read this first
1.1.110 and other past stables — but there's a quirk documented across multiple bug-report threads: if you own Space Age and it's enabled, the downgrade doesn't take. The expansion requires the 2.0 executable, so Steam quietly keeps you on it. The fix is one checkbox: Properties → DLC tab → untick Space Age, then pick the branch. People have reinstalled the game over this; it's a checkbox. This is the one that bit me — my downgrade silently snapped back to 2.0 twice before I spotted the DLC tab.
02Wube's full archive — the best shelf in this series
Factorio is sold DRM-free with a developer account system, and your Steam copy links into it: register at factorio.com with your Steam ownership and the site's download page offers archived releases of every version of the game — not a curated handful, the catalog — in ZIP flavors that are fully self-contained: unzip anywhere, run, no installer, no Steam, no launch surgery. Side-by-side eras aren't a community trick here; they're the product working as designed. On my own machine I keep a 1.1.110 ZIP unzipped next to my 2.0 install, and the two have never once touched each other. Measured against everything this series has catalogued — one-slot branches, unlisted apps, vanished alphas — this is the gold standard: the developer simply keeps everything, for every owner, forever so far. DepotDownloader's role in this game is correspondingly honest and small: pulling the Steam-side branch into a folder if you prefer your tooling uniform, and nothing more — the archive does the rest better.
03Saves are strictly forward
The era line is sharp in the save format: a save made or even overwritten in 2.0 won't load in 1.1.110. The community's standard answer — endorsed in the forum threads — is the dual install: your 1.1 era (archive ZIP or branch) carries the old saves and megamod campaigns to their natural conclusion, while 2.0/Space Age lives separately. User data sits in %APPDATA%\Factorio\ (saves, mods, config) for installed copies, while the self-contained ZIPs can keep everything local to their folder — one more point to the archive route, since eras then can't contaminate each other's saves at all. Back up before experiments regardless; megabases deserve the respect.
04The mod portal remembers everything
Factorio's mod ecosystem matches its version ecosystem. The official mod portal keeps every past release of every mod downloadable, each tagged with its supported game version — the property whose absence makes RimWorld's Workshop a trap and whose presence makes era-pinning routine here. Better: the in-game mod manager fetches versions compatible with your build, so a 1.1.110 install assembles a 1.1-era modpack semi-automatically — the CKAN-tier era bookkeeping, built in. A 1.1 install plus the portal equals any historical modpack, reproducible years later.
05Headless servers per version
Multiplayer matches versions exactly, and the server side follows the same generous pattern: Wube publishes the headless server build for every version on the same downloads page, free to grab, so a community pinned to a 1.1 megamod campaign downloads the matching headless ZIP and runs — no Steam dance, no depot work, the version chosen by filename. It's the only game in this series where the server-pinning chapter is one sentence long, and that's the compliment.
06Status in 2026
Factorio closes the survey as the counterweight to every cautionary tale before it. TF2 lost its pre-2013 history; 7DTD's museum has an empty case; GTA V's Legacy got unlisted — and Wube just… keeps everything, on their own infrastructure, immune to manifest weather entirely, with the mod portal preserving the ecosystem around it. The asterisks are honest but small: the archive requires a factorio.com login, saves only travel forward, and the DLC checkbox will eat an afternoon if you don't know about it. The lesson for the series is the one worth ending on: preservation is a developer choice, and this is what choosing it looks like. For every game whose developer chose otherwise, the rest of this site exists.