FACTORIO 2.1: GROUP SERVER UPGRADE CHECKLIST
GHosting | Checked 2026-10-27 against headless 2.1.23
Guide: https://ghosting.gg/blog/factorio-2-1-server-update

BEFORE CHANGING THE LIVE SERVER
[ ] Record the exact working server/client version and every enabled mod version.
[ ] Save and stop cleanly. Wait for the process to exit.
[ ] Copy the save ZIP, complete mods folder (including mod-list.json and
    mod-settings.dat if present), server configuration and startup command.
[ ] Keep the backup outside the running installation.
[ ] Back up each player's blueprint-storage*.dat while their game is closed.
[ ] Keep the older runtime or a way to obtain that exact release.
[ ] For asteroid reprocessing, remove Quality modules into storage in 2.0,
    then save a prepared copy as well as keeping the untouched original.

PREPARE AN ISOLATED COPY
[ ] Use a separate write-data directory; copy the save instead of moving it.
[ ] Check official mod releases for Factorio 2.1 and their dependencies.
[ ] Check recycler explicitly in the enabled component set.
[ ] Do not replace an established mod list with a new-world example.
[ ] Disable public listing on a private test server.
[ ] Select the test ZIP explicitly rather than guessing which save is newest.

INSPECT THE FACTORY IN 2.1
[ ] Confirm the loading log names the expected ZIP and reaches the running state.
[ ] Join with a matching client. Verify the expected factory and player state.
[ ] Inspect assembler and asteroid-collector circuits that both read and write.
[ ] Check input/output wire colours against what each network is meant to carry.
[ ] Inspect asteroid reprocessing recipes, module inventories and downstream supply.
[ ] Fly one complete supply route, including the return flight.
[ ] Check fuel, ammunition, repair packs, damage, deliveries and replenishment.
[ ] For platform transfers, check both source selection and provider permission.
[ ] Verify one science, fuel or ammunition line through a whole production cycle.
[ ] Inspect perimeter supplies and radar coverage.
[ ] Save, stop, reload and repeat the critical checks.

SWITCH THE GROUP
[ ] Agree an exact target version and restart window with every player.
[ ] Take a fresh final backup before changing the live environment.
[ ] Update runtime and compatible mods while preserving persistent data.
[ ] Read the loading log, join once, check the factory, then invite the group.
[ ] Retain the recovery copy until the group has played successfully.

IF ROLLBACK IS NECESSARY
Restore the pre-2.1 save WITH the matching older runtime, mods and settings.
Clients need the compatible older game version too. A converted 2.1 save cannot
be made 2.0-compatible by swapping only the executable. Changes made in 2.1
will not be present in the pre-upgrade backup.

These are suggested checks, not certification for every factory or mod pack.
No customer saves were used for the article's tests.