Highly Performant & Scalable Ultima Online Server Emulator https://www.modernuo.com
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Kamron Batman b34c8b32ef
perf(login): move password writes off-loop too, behind one mechanism
SetPassword derives a full Argon2 hash, so the [password command, the admin
gump, account creation and the XML import each cost ~8.9 ms of frozen world.
Only the login verify had been moved.

DRY-ing the two paths surfaced a correctness trap rather than just shared
code. ApplyPasswordUpgrade guarded by comparing the stored hash, which is
right for a login rehash -- do not clobber a newer password with a rehash of
the one it superseded -- but wrong for an explicit change: two changes
dispatched before either landed would drop the second and silently keep the
older password. Ordering is now a per-account dispatch sequence claimed on
the loop, which gives "newest wins" for both callers through one mechanism.
SetPassword bumps it as well, so an inline write also supersedes an in-flight
one.

One job type serves both: PasswordJob carries an optional verify phrase and
an optional hash phrase plus an OnComplete that runs on the loop, so a login
verifies and may rehash while a password change only hashes. The class is
PasswordWorker now, since verification no longer describes what it does.

PasswordWorker.SetPassword is the single entry point and falls back to
hashing inline when the gate is off or the queue is saturated -- unlike a
login, a password change must never be silently dropped, and it is rare
enough that the loop can absorb one.

The [password confirmation moves into the callback, because off the loop it
has not happened when the call returns. Account creation stays inline: it
gates the login flow, so deferring it restructures the accept path.
2026-08-08 12:25:49 -07:00
.config feat: Adds Build Tool for Publishing/Setup (#2392) 2026-03-28 21:21:50 -07:00
.github fix: Require only runtime packages on Linux, and check ICU and tzdata the way the runtime does (#2561) 2026-08-07 15:03:08 -07:00
branding feat(build-tool): add application icon and refresh MUO.ico (#2487) 2026-06-14 11:59:54 -07:00
dev-docs perf(login): move password writes off-loop too, behind one mechanism 2026-08-08 12:25:49 -07:00
Distribution/Data fix(throwing): grant Str/Dex stat gains for the Throwing skill (#2514) 2026-07-02 23:07:36 -07:00
Projects perf(login): move password writes off-loop too, behind one mechanism 2026-08-08 12:25:49 -07:00
tools feat(network): allowlist false-positive IPs, escalate on behavior (#2556) 2026-07-30 23:12:17 -07:00
.cursorrules chore: Adds AI instructions and SKILLs for ModernUO codebase (#2347) 2026-03-01 11:42:19 -08:00
.editorconfig chore(docs): Adds UnmanagedDataReader & BinaryFileReader documentation (#1968) 2024-10-01 17:07:51 -07:00
.gitattributes fix: Adds migration checks to CICD, updates dependencies, adds Fedora 37, alpine 3.17 support (#1309) 2022-12-22 12:12:47 -08:00
.gitignore feat(network): allowlist false-positive IPs, escalate on behavior (#2556) 2026-07-30 23:12:17 -07:00
AGENTS.md chore: Adds AI instructions and SKILLs for ModernUO codebase (#2347) 2026-03-01 11:42:19 -08:00
azure-pipelines.yml chore: Cleans workflows for NodeJS 24 (#2394) 2026-03-28 21:55:29 -07:00
CLAUDE.md docs: state when a background thread is justified, and trim the sweep 2026-08-08 11:37:03 -07:00
CODE_OF_CONDUCT.md Create CODE_OF_CONDUCT.md 2020-05-05 08:51:39 -07:00
CONTRIBUTING.md chore(license): Removes CLA requirement. All contributors moving forward will retain copyright. (#2038) 2024-12-31 02:52:58 -08:00
Directory.Build.props fix: Bumps dependencies. (#2531) 2026-07-14 15:17:55 -07:00
FAQ.md docs: Updates FAQ for time zone issues. (#1368) 2023-03-10 00:18:36 -08:00
GEMINI.md chore: Adds AI instructions and SKILLs for ModernUO codebase (#2347) 2026-03-01 11:42:19 -08:00
global.json feat: Adds Build Tool for Publishing/Setup (#2392) 2026-03-28 21:21:50 -07:00
LICENSE Fixes more line ending issues (#267) 2020-09-27 13:54:56 -07:00
ModernUO.slnx feat: Adds Build Tool for Publishing/Setup (#2392) 2026-03-28 21:21:50 -07:00
publish.cmd feat: Adds Build Tool for Publishing/Setup (#2392) 2026-03-28 21:21:50 -07:00
publish.ps1 fix: Adds stamp check for build tool versioning (#2400) 2026-04-06 16:18:02 -06:00
publish.sh fix: Adds stamp check for build tool versioning (#2400) 2026-04-06 16:18:02 -06:00
README.md fix: Require only runtime packages on Linux, and check ICU and tzdata the way the runtime does (#2561) 2026-08-07 15:03:08 -07:00
rider-settings.zip Cleanup/Housekeeping (#242) 2020-09-12 15:31:21 -07:00
Rules.ruleset chore(docs): Adds UnmanagedDataReader & BinaryFileReader documentation (#1968) 2024-10-01 17:07:51 -07:00
SPONSORS.md chore: Updates readme files (#2247) 2025-07-27 11:04:32 -07:00
stylecop.json Updates formatting rules (#199) 2020-08-25 18:00:51 -07:00
THIRD-PARTY-NOTICES docs: Adds RunUO-Encryption notice attribution to DarkStorm (#2369) 2026-03-12 23:35:47 -07:00
version.json feat: Adds Build Tool for Publishing/Setup (#2392) 2026-03-28 21:21:50 -07:00

ModernUO - Ultima Online Server Emulator for the modern era!

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Ultima Online Server Emulator for the modern era!

GitHub license GitHub stars GitHub issues
GitHub build Azure Pipelines build

Requirements

Supported Operating Systems

Windows 10/11/2012/2016/2019/2022/2025 MacOS 14+ Debian 12+ Ubuntu 22+ LTS
Alpine 3.22+ Fedora 42+ RedHat 9+ CentOS Stream 9+ AlmaLinux 10 openSUSE 15.6+ SUSE Enterprise 15 SP6 Linux Mint 21+ Arch

Required Frameworks

All Operating Systems

.NET

Windows

VC++ Redistributable v14

Development

git .NET

Supported IDEs

Jetbrains Rider 2025.3+ space VSCode space Visual Studio 2026

Getting Started

  • Install prerequisite requirements
  • Clone this repository (or download the latest):
    • git clone https://github.com/modernuo/ModernUO.git
  • Open ModernUO.sln to start developing

Building/Publishing

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 Distribution directory
  • Show deployment instructions for cross-compiled builds

Command Line

./publish.cmd [release|debug] [os] [arch]

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 Distribution directory is portable — copy it to your production server for deployment
  • Run ModernUO.exe or dotnet ModernUO.dll from the Distribution directory
  • On first run, the server will prompt you to configure game data file locations

Troubleshooting / FAQ

Want to sponsor?

Thank you for supporting us! You can find out how by visiting the sponsors page.

Collaborators

Kamron Batman Mark1145

Thanks

  • RunUO Team & Community
  • Voxpire, the ServUO Team & Community
  • Karasho, Jaedan and the ClassicUO Community



Development Tools & Plugins provided with ♥ by

JetBrains
Material Theme

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