Highly Performant & Scalable Ultima Online Server Emulator
https://www.modernuo.com
c-sharpcsharpcsharp-coredotnetdotnet-coreemulatorgplgplv3mmommo-enginemmorpgmmorpg-serveronlinerpgrunuoserverservuoultimaultima-onlineuo
bd79cb7759
Follow-up to #2573. That change made `SmallBOD.EndCombine` require a player-crafted item, but it could only read provenance off `BaseArmor`, `BaseWeapon` and `BaseClothing`, because those are the only three classes that track it — hence the hand-enumerated `armor?.PlayerConstructed ?? clothing?.PlayerConstructed ?? weapon?.PlayerConstructed ?? false`. The gap is structural rather than cosmetic. `PlayerConstructed` is set inside each base's `OnCraft`, so it can only ever reach types implementing `ICraftable`. Most craftables do not — the tinkering catalogue alone is largely plain `Item` subclasses — so any rule keyed on "was this actually crafted" has nothing to key on for those types. ## What changed Provenance moves to `Item` and is stamped centrally in `CraftItem`, immediately after the item is constructed and before the `ICraftable` dispatch, covering both the AOS and T2A craft paths. The three `OnCraft` overrides drop their now-redundant assignment and inherit `Item`'s property, so no call site outside them changes — `Resmelt` and `SalvageBag` still read `armor.PlayerConstructed` and still compile unchanged. `SmallBOD`'s three-way null-coalescing chain collapses to `item.PlayerConstructed`. `OnCraft` is only ever invoked from `CraftItem` (the other three call sites are `base.OnCraft` chaining), so removing those assignments has no other reachable effect. ## Storage cost: none `Item`'s `SaveFlag` word is written as a fixed-width `int`, not an encoded one, so occupying bit `0x08000000` changes no record lengths. Items that are not player-constructed serialize byte for byte as before, and crafted ones differ by a single bit in a field already being written. `Item` itself needs no version bump: a bare `SaveFlag` bit is self-describing, so records written before it existed lack it and read `false`. ## Version bumps The three content classes do need one, since removing a serialized field changes their layout: | Class | Version | Field removed | |---|---|---| | `BaseArmor` | 9 → 10 | 24 (was last, nothing renumbered) | | `BaseClothing` | 7 → 8 | 7 (fields 8–10 shift down) | | `BaseWeapon` | 10 → 11 | 26 (fields 27–30 shift down) | Each gets a `MigrateFrom` for its previous version that assigns the old bool to the inherited property, so existing crafted armour, weapons and clothing keep their provenance across the upgrade. `Item.Deserialize` runs first and reads the absent bit as `false`, then the migration overwrites it — the generated `Deserialize` calls `base.Deserialize` before dispatching, so the ordering holds. `BaseWeapon` had no migrations file and gains one. The renumbering is not stylistic: the generator requires contiguous field ordering and rejects a hole with `SG3005: Expected field 'Crafter' with order 7 but found 8`. New schema JSONs (`BaseArmor.v10`, `BaseClothing.v8`, `BaseWeapon.v11`) are generated by `ModernUOSchemaGenerator` and committed alongside. ## One thing worth a second opinion The new property is a plain auto-property on `Item`, so it does not call `this.MarkDirty()` the way the codegen setters it replaces did. `MarkDirty` is currently a no-op (`// TODO: Add dirty tracking back`) and no property in `Item.cs` calls it, so this matches the file as it stands — but it is worth noting if dirty tracking comes back. ## Verification Full solution builds in Release with 0 errors and 0 warnings; 1516 tests pass (815 `Server.Tests`, 701 `UOContent.Tests`). |
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| Distribution/Data | ||
| Projects | ||
| tools | ||
| .cursorrules | ||
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| .gitattributes | ||
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| AGENTS.md | ||
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| CLAUDE.md | ||
| CODE_OF_CONDUCT.md | ||
| CONTRIBUTING.md | ||
| Directory.Build.props | ||
| FAQ.md | ||
| GEMINI.md | ||
| global.json | ||
| LICENSE | ||
| ModernUO.slnx | ||
| publish.cmd | ||
| publish.ps1 | ||
| publish.sh | ||
| README.md | ||
| rider-settings.zip | ||
| Rules.ruleset | ||
| SPONSORS.md | ||
| stylecop.json | ||
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| version.json | ||
ModernUO 
Ultima Online Server Emulator for the modern era!
Requirements
Supported Operating Systems
Required Frameworks
All Operating Systems
Windows
Hardware
| Use | vCPU | RAM | Storage |
|---|---|---|---|
| Development / test | 2 dedicated | 2 GB | SSD |
| Small live shard (< 50 concurrent) | 4 dedicated | 4 GB | NVMe |
| Medium (50–200) | 4–8 | 8 GB | NVMe |
| Large (200+) | 8+, high clock | 16 GB+ | NVMe |
Game logic is single-threaded, so single-core clock speed matters more than core count, and dedicated vCPU matters more than either — burstable or shared plans throttle once credits run out, which is the most common cause of unexplained lag spikes. Save size drives RAM more than player count does.
See dev-docs/server-requirements.md for the reasoning and tuning options.
Development
Supported IDEs
Getting Started
- Install prerequisite requirements
- Clone this repository (or download the latest):
git clone https://github.com/modernuo/ModernUO.git
- Open
ModernUO.slnto start developing
Building/Publishing
Interactive Mode (Recommended for new users)
Run ./publish.cmd (Windows) or ./publish.sh (Linux/macOS) with no arguments to launch the guided build tool. It will:
- Check prerequisites (.NET SDK, native libraries)
- Walk you through configuration and platform selection
- Build and publish the server to the
Distributiondirectory - Show deployment instructions for cross-compiled builds
Command Line
./publish.cmd [release|debug] [os] [arch]
os- Supported operating systemsarchx64- Intel/AMD 64-bitarm64- ARM 64-bit
Linux Prerequisites
Fedora, CentOS, RHEL, AlmaLinux, Rocky, etc
dnf upgrade --refresh -y
# RHEL-family distributions (CentOS Stream, AlmaLinux, Rocky, RHEL) need CRB and EPEL enabled.
# Fedora skips this block.
dnf install -y dnf-plugins-core
dnf config-manager --set-enabled crb
dnf install -y epel-release
# Prerequisites
dnf install -y findutils libicu libdeflate libargon2 tzdata
Ubuntu, Debian, etc
apt-get update -y
# The ICU runtime package carries the ABI version in its name (libicu74, libicu76, …) and has no
# stable alias, so match it by pattern rather than pinning a release-specific name.
apt-get install -y '^libicu[0-9]+$' libdeflate0 libargon2-1 tzdata
Only the runtime libraries are needed — the -dev/-devel packages are not. Run
./build-tool --check-prereqs to check the current machine and print the exact packages your
release needs.
zstd is not listed because ZstdNet bundles libzstd for every platform, and liburing is not
listed because IORingGroup issues io_uring syscalls directly.
If the shard's configured time zone is a legacy alias such as US/Eastern, Debian 12 and Ubuntu
24.04 also need tzdata-legacy. See Platform Prerequisites
for what each dependency is for and what breaks without it.
OSX Requirements
brew install icu4c libdeflate argon2
Running the Server
- Follow the publish instructions
- The
Distributiondirectory is portable — copy it to your production server for deployment - Run
ModernUO.exeordotnet ModernUO.dllfrom theDistributiondirectory - On first run, the server will prompt you to configure game data file locations
Troubleshooting / FAQ
- See FAQ
Want to sponsor?
Thank you for supporting us! You can find out how by visiting the sponsors page.
Collaborators
Thanks
- RunUO Team & Community
- Voxpire, the ServUO Team & Community
- Karasho, Jaedan and the ClassicUO Community
Development Tools & Plugins provided with ♥ by
Code Signing Policy
Free code signing provided by SignPath.io, certificate by SignPath Foundation.
This program will not transfer any information to other networked systems unless specifically requested by the user or the person installing or operating it
Teams & Roles
Approvers & Committers: Development Team