Valheim Upgrade World mod: new content in old worlds

Upgrade World by JereKuusela is the mod that puts new update content into the parts of a Valheim world you have already explored. It adds admin console commands that reset zones so they regenerate, add new dungeons and camps into generated land, and switch an old world to a newer biome layout. On a dedicated server it goes on the server and on the admin's own game, you run upgrade <operation>, read the preview, type start, and then remove the mod. Take a backup before every run, because a reset zone loses everything in it and the mod's base protection is good but not perfect.

This post covers when you need it, how to install it on a dedicated server, the commands that matter, how base protection works, and a procedure that keeps the world recoverable if something goes wrong.

What Upgrade World does and why vanilla cannot#

Valheim generates each 64 metre zone once, the first time a player comes near it, and stores the result in the world. After that, the seed is never consulted for that zone again. When an update adds a biome or a dungeon, only zones generated after the update get it. Old worlds and new biomes explains the mechanism in full.

Vanilla Valheim has no command that undoes generation. Upgrade World fills that gap with three kinds of operation:

• Zone resets. A reset zone is cleared and regenerates from the seed with the current generator the next time someone visits. This is how an explored placeholder north becomes the Deep North.
• Location additions. New locations - a trader camp, a dungeon, a cave - are placed into zones that already exist, without resetting them.
• World generation version. The biome layout of a world created before Mistlands can be switched to the newer one, or an old layout restored.

It also has a long list of utility commands: rerolling chest loot, counting or removing objects, cleaning up broken data, adding vegetation, and pre-generating zones. Most servers need four or five commands; the rest are there when you need them.

The mod is an editor, not a compatibility patch. Nothing happens until you tell it to, and once you remove it the world is a normal vanilla world again with the changes baked in.

When to use it, and when not to#

Upgrade World is the right tool when a group has a world worth keeping and wants specific new content near it. Typical cases:

It is the wrong tool when the world is due for a fresh start anyway, when the bases are on land the operation would touch and nobody wants to risk them, or when unexplored land is a voyage away. Sailing further costs nothing and risks nothing. If you are not sure, read when a fresh world is the honest answer first.

Two operations deserve extra caution. mistlands_worldgen switches an old world to the Mistlands-era biome distribution: outer areas change, areas past 5,900 metres from the centre reset, and rivers can move and destroy bases. legacy_worldgen and hh_worldgen go the other way. Treat any world generation change as a big decision for the group, not an admin's quiet evening job.

Installing it on a dedicated server#

Upgrade World is a BepInEx plugin, published on Thunderstore. The mod page asks for it on the server and on the admin client - the game of whoever will type the commands. Other players do not need it.

1. Check the version. The Thunderstore page lists the mod version and its required dependencies. Make sure the release you download supports the game version your server runs; after a major patch, wait for an update rather than forcing an old one.
2. Install BepInEx on the server if it is not there already. The BepInExPack for Valheim unpacks into the server root and changes the start command. Valheim mods with BepInEx on a server has the full install.
3. Put the mod's `.dll` in `BepInEx/plugins` on the server, along with any dependencies listed on its page. Upload over SFTP or the file manager while the server is stopped.
4. Install the same version on your own game, normally through r2modman or Thunderstore Mod Manager, so the admin client matches.
5. Start the server once. The config file appears at BepInEx/config/upgrade_world.cfg.
6. Enable your console. In Steam, add -console to Valheim's launch options. In game, F5 opens it.
7. Make sure you are an admin. Your ID must be in adminlist.txt on the server. The admin, ban and allow lists shows the ID formats, which changed again with 1.0.

By default every admin can run the mod's commands. If your admin list is long, use the root users setting in the config to restrict them to specific IDs; -1 stands for the dedicated server itself.

The mod also adds coordinates and zone indices to the minimap on the admin client, which is useful for working out where an operation will land.

The commands that matter#

Every command prints a preview of what it will do and waits. Nothing changes until you type start. Tab completes command names and operation names.

upgrade deepnorth        # preview: which zones would be resetstart                    # run ituw_check                 # list queued operationsstop                     # cancel what is queued or running

The upgrade shortcuts cover the common cases:

Underneath, the shortcuts are built from general commands you can use directly:

• zones_reset clears zones so they regenerate when next visited. It also shrinks the world file, since a reset zone holds no data until it is generated again.
• locations_add [ids] places locations into explored areas without resetting anything else.
• locations_reset [ids] removes and re-places locations, giving dungeons with random layouts a new layout.
• locations_list [ids] and biomes_count report what exists, changing nothing.
• chests_reset replaces chest contents, with options for looted chests and specific items.
• objects_count [ids] and objects_remove [ids] find and remove objects. Count before removing.
• world_clean runs all the clean_* routines that repair broken data.

Most commands take filters. The ones you will use:

zones_reset biomes=Mountain min=4000zones_reset pos=1200,-3400 max=500locations_add biomes=Swamp

The first line resets every Mountain zone more than 4 km from the centre; the second resets everything within 500 metres of one point; the third adds missing locations to explored Swamps. What each filter means:

• biomes= limits the operation to listed biomes: Meadows, BlackForest, Swamp, Mountain, Plains, Mistlands, AshLands, DeepNorth, Ocean.
• min= and max= set distance bounds from the centre, or from pos= if you give one.
• pos=x,z centres the operation on a position; zone=x,z on a zone index.
• safeZones= sets the base protection size; 0 or force disables it.
• noEdges only includes zones whose corners are all in the listed biomes, which avoids clipping a neighbouring biome.

Base protection and how it fails#

Upgrade World detects bases and skips the zones around them. By default it treats player-built structures that carry the base effect - the pieces that stop monsters spawning nearby, such as workbenches and fires - as a base, and also protects zones with a tombstone in them. Each detected structure protects its own zone and one ring of neighbours, a 3 by 3 block of zones, about 192 metres square.

That default is conservative: a single campfire or workbench protects a large area. It is also exactly where things go wrong:

• Builds without a base piece are not protected. A bridge, a road, a wall around a field, a dock or a portal shed with no workbench or fire nearby can be wiped.
• Large bases can spill out of the protected block. A base 300 metres across with one workbench in the middle has edges outside the 3 by 3 block.
• Terrain work is in the zone too. A levelled area or a canal in an unprotected zone regenerates as natural ground.
• Portals in the reset area disappear, and portals elsewhere may need a relog to reconnect.

Two habits handle most of this. First, before running a reset, have players drop a workbench at the far corners of anything they want kept; it costs ten wood each and the base detection does the rest. Second, run the preview and read it. The mod tells you how many zones it will touch; if that number is far higher than you expected, stop and narrow the filters.

A safe procedure on a live server#

This is the order that keeps a world recoverable.

1. Agree a time with the group and ask everyone else to log off. Zones are owned by whoever is nearest, and fewer moving parts make for fewer surprises.
2. Take a backup and copy it off the server. On RE:NODE, run a backup from the Backups tab and lock it so scheduled rotation cannot remove it. Also download it. Valheim backups and world corruption explains why a copy beside the world is not enough.
3. Test on a copy first if the operation is big. Copy the world into your own game's worlds_local folder, open it in single player with the same mods, and run the same commands. Since 1.0 a world is stored in a new chunked format; copy everything belonging to the world, not just one file.
4. Install the mod on the server and your client, restart the server, and join.
5. Run the preview, read the zone count, then start. Wait for it to finish.
6. Check every base. Fly or walk round the edges. If anything is missing, stop the server and restore the backup, then try again with a larger safeZones or tighter filters.
7. Save and restart cleanly so the result is on disk.
8. Remove the mod from the server and your client. The README recommends this, and it stops anyone running a command by accident later.

Reset zones regenerate when somebody visits them. Nothing new appears until a player sails out there, which is also when you will see whether the new content placed sensibly.

Troubleshooting#

The command is not recognised. The mod is not loaded on your client, or your client and the server have different versions. Check BepInEx/LogOutput.log on both sides for the plugin loading line.

"Not allowed" or nothing happens. You are not an admin, or the root users setting is set and does not include your ID. Check the ID the server log prints when you join against both lists.

The preview says zero zones. The filters exclude everything, or base protection covers the whole area. Try biomes_count to see what the mod thinks is there, then loosen one filter at a time.

A base was damaged. Restore the backup. Do not try to rebuild over a half-reset area; terrain and object data from the old and new generation can overlap badly.

Portals stopped connecting. Relog. If a portal was in a reset zone, it is gone and needs rebuilding.

The new content did not appear. Reset zones only regenerate when visited. Sail out and look. If it is still missing, the location may simply not be planned near there by the seed; locations_list shows where the game placed them.

FAQ#

Do players need Upgrade World installed to join?

No. The mod page asks for it on the server and on the admin client that runs the commands. Once the work is done you can remove it from both, and the world stays changed.

Will Upgrade World delete my base?

Not if base detection recognises it and the base fits inside the protected zones. It protects a 3 by 3 block of zones around each base structure by default. Anything outside that, or without a workbench or fire nearby, can be reset. Back up first.

Can I use it to bring the Deep North into an old world?

Yes. upgrade deepnorth regenerates the northern biome and nearby water using the 1.0 generator. Any building in that area that the base detection misses will be lost, so check before running it.

Does it work on a crossplay server?

The commands run on the server and the admin's PC, so crossplay does not change how it works. Console players cannot install mods, so the admin needs to be on PC. Players on Xbox can join as normal once the mod's work is done.

Is it safe to leave installed?

It does nothing until an admin runs a command, but leaving a world editor on a live server invites mistakes. Remove it when you are finished and reinstall it next time you need it.