How to Update MuServer Version Without Losing Data

Updating MuServer from one version to another is one of the riskiest operations in private server administration. Done without planning, it results in permanent loss of player data. Done correctly, it is a controlled process that typically requires 2 to 4 hours of planned downtime.

This guide covers migration between compatible versions — for example, from Season 6 Episode 1 to Season 6 Episode 3, or from Season 9 to Season 12. Migrations between very distant seasons (e.g., S6 to S13) require additional intermediate steps not covered here and must be done in stages.

Before You Start: Assessing Compatibility

Not every MuServer update is straightforward. Database tables change between versions, and configuration files gain new mandatory keys.

Identifying your current version

Open GameServer/GameServer.ini and locate:

[Version]
ServerVersion = 1.04.0
GameVersion   = 0.99.60T

Compare with the target version. If GameVersion changes significantly, there will be database schema changes that must be applied before starting the new binaries.

Identifying available migration scripts

Every MuServer package includes a DBUpdate/ or SQL/ folder with numbered migration scripts. Before proceeding, list those scripts:

DBUpdate/
  001_AddColumnResetCount.sql
  002_CreateTableEventRanking.sql
  003_AlterTableCharacter.sql
  004_InsertDefaultEventSchedule.sql

If the package does not include SQL scripts, you will need to manually compare schemas in SQL Server Management Studio (SSMS) — compare sys.columns on the current database versus a fresh database created with the new version.

Step 1: Full Backup — No Exceptions

Run in SSMS before any other action:

-- Full backup with automatic timestamp
DECLARE @BackupPath NVARCHAR(500)
SET @BackupPath = 'C:\Backups\MuOnline_pre_update_' +
    REPLACE(REPLACE(CONVERT(VARCHAR, GETDATE(), 120), ':', '-'), ' ', '_') + '.bak'

BACKUP DATABASE MuOnline
TO DISK = @BackupPath
WITH FORMAT, INIT, COMPRESSION,
     NAME = 'MuOnline Full Backup Pre-Update',
     STATS = 10;

PRINT 'Backup saved to: ' + @BackupPath

After the backup, verify the file is not corrupted:

RESTORE VERIFYONLY FROM DISK = 'C:\Backups\MuOnline_pre_update_2026-07-03_22-00-00.bak';
-- Expected result: "The backup set on file 1 is valid."

Also back up configuration files:

xcopy /E /I /Y "C:\MuServer\GameServer\Data" "C:\Backups\GameServer_Data_backup"
xcopy /E /I /Y "C:\MuServer\ConnectServer" "C:\Backups\ConnectServer_backup"
xcopy /E /I /Y "C:\MuServer\DataServer" "C:\Backups\DataServer_backup"
xcopy /E /I /Y "C:\MuServer\EventServer" "C:\Backups\EventServer_backup"

Step 2: Shut Down All Services in the Correct Order

Shut down in this sequence to prevent corrupted data writes:

1. Close the web admin panel (if running)
2. Terminate GameServer.exe — wait for the process to fully disappear from Task Manager
3. Terminate EventServer.exe
4. Terminate DataServer.exe
5. Terminate ConnectServer.exe

Step 3: Create a Test Database and Validate SQL Scripts

Never apply migration scripts directly to the production database without testing first. Restore a test copy:

RESTORE DATABASE MuOnline_Test
FROM DISK = 'C:\Backups\MuOnline_pre_update_2026-07-03_22-00-00.bak'
WITH MOVE 'MuOnline'     TO 'C:\SQLData\MuOnline_Test.mdf',
     MOVE 'MuOnline_log' TO 'C:\SQLData\MuOnline_Test_log.ldf',
     REPLACE, STATS = 10;

With the test database ready, run the migration scripts in numerical order. Typical script for adding a new column:

USE MuOnline_Test;
GO

-- 001_AddColumnResetCount.sql
IF NOT EXISTS (
    SELECT 1 FROM INFORMATION_SCHEMA.COLUMNS
    WHERE TABLE_NAME = 'Character' AND COLUMN_NAME = 'ResetCount'
)
BEGIN
    ALTER TABLE dbo.Character ADD ResetCount SMALLINT NOT NULL DEFAULT 0;
    PRINT 'OK: Column ResetCount added.';
END
ELSE
    PRINT 'SKIP: Column ResetCount already exists.';
GO

Example script to create a new event ranking table:

-- 002_CreateTableEventRanking.sql
USE MuOnline_Test;
GO

IF OBJECT_ID('dbo.EventRanking', 'U') IS NULL
BEGIN
    CREATE TABLE dbo.EventRanking (
        RankID      INT IDENTITY(1,1) PRIMARY KEY,
        CharName    VARCHAR(10)  NOT NULL,
        EventType   TINYINT      NOT NULL,  -- 1=BloodCastle, 2=DevilSquare, 3=ChaosC
        Score       INT          NOT NULL DEFAULT 0,
        RankDate    DATETIME     NOT NULL DEFAULT GETDATE(),
        ServerCode  TINYINT      NOT NULL DEFAULT 0
    );
    PRINT 'OK: Table EventRanking created.';
END
ELSE
    PRINT 'SKIP: Table EventRanking already exists.';
GO

After running each script, check the "Messages" tab in SSMS. Any line with Msg followed by an error number must be investigated before proceeding.

Step 4: Replace Server Binaries

With scripts validated on the test database, replace the executables. Target structure:

C:\MuServer\
  GameServer\
    GameServer.exe        <- replace with new
    GameServer.ini        <- MERGE (compare and transfer your values)
    Data\
      Monster\            <- replace all contents with new version
      Events\             <- replace all contents with new version
      Maps\               <- replace all contents with new version
  ConnectServer\
    ConnectServer.exe     <- replace with new
    ConnectServer.ini     <- MERGE (check for new keys)
  DataServer\
    DataServer.exe        <- replace with new
    DataServer.ini        <- MERGE (confirm connection string)
  EventServer\
    EventServer.exe       <- replace with new

Typical diff in GameServer.ini when upgrading to Season 9+:

; NEW key in the target version — add to your GameServer.ini
[RefinementSystem]
Enable = 1
MaxRefinementLevel = 15
RefinementFailRate = 30

; EXISTING key — keep your current value
[GameServerInfo]
ServerCode = 0
MaxUser = 300
ServerName = Your MU Server

Step 5: Set Database Compatibility Level (if needed)

If the new MuServer version requires a specific SQL Server compatibility level:

-- Check current level
SELECT name, compatibility_level FROM sys.databases WHERE name = 'MuOnline';

-- SQL Server 2008 / Season 6 (level 100)
ALTER DATABASE MuOnline SET COMPATIBILITY_LEVEL = 100;

-- SQL Server 2012 / Newer seasons (level 110)
-- ALTER DATABASE MuOnline SET COMPATIBILITY_LEVEL = 110;

-- SQL Server 2017/2019 (level 140)
-- ALTER DATABASE MuOnline SET COMPATIBILITY_LEVEL = 140;

Step 6: Apply Migration to Production Database

After full validation on the test database, apply the same scripts to the real database:

USE MuOnline;
GO
-- Run scripts in order:
-- 001_AddColumnResetCount.sql
-- 002_CreateTableEventRanking.sql
-- 003_AlterTableCharacter.sql
-- (etc.)

Step 7: Start Services and Validate

Start in the correct order:

1. ConnectServer.exe
2. DataServer.exe
3. EventServer.exe
4. GameServer.exe

Monitor logs immediately after each start:

GameServer\Log\GameServer_YYYYMMDD.log
DataServer\Log\DataServer_YYYYMMDD.log

Most common errors and their causes:

[ERROR] Table 'Character' column 'ResetCount' not found
→ Script 001 was not applied to the production database. Run it on MuOnline.

[ERROR] Could not connect to DataServer on 127.0.0.1:55900
→ DataServer did not start or port changed. Check DataServer.ini and restart.

[ERROR] Map file not found: Data/Maps/Devias.att
→ New version map files were not copied. Repeat Step 4.

Run post-migration validation queries:

USE MuOnline;

-- Character count (compare with pre-migration numbers)
SELECT COUNT(*) AS TotalCharacters FROM Character;

-- Verify item integrity
SELECT COUNT(*) AS CharactersWithoutItems
FROM Character
WHERE Items IS NULL OR DATALENGTH(Items) = 0;
-- Expected result: 0

-- Verify guilds are intact
SELECT COUNT(*) AS TotalGuilds FROM Guild;

-- Clear stuck sessions (common after restart)
UPDATE MEMB_STAT SET ConnectStat = 0, ServerName = '' WHERE ConnectStat = 1;

Event Verification After Migration

If events are not triggering at the correct times:

USE MuOnline;

-- Check event schedules configured in the database
SELECT * FROM EventSchedule ORDER BY EventType;

-- Reconfigure Blood Castle schedule (EventType = 1)
UPDATE EventSchedule
SET StartTime1 = '09:00', StartTime2 = '13:00',
    StartTime3 = '17:00', StartTime4 = '21:00',
    Duration = 60
WHERE EventType = 1;

-- Reconfigure Devil Square schedule (EventType = 2)
UPDATE EventSchedule
SET StartTime1 = '10:00', StartTime2 = '14:00',
    StartTime3 = '18:00', StartTime4 = '22:00',
    Duration = 30
WHERE EventType = 2;

If events are configured via .ini files instead of the database (common in older Season 6 builds):

; GameServer\Data\Events\BloodCastle.ini
[BloodCastle]
Enable = 1
Open_Time1  = 09:00
Close_Time1 = 10:00
Open_Time2  = 13:00
Close_Time2 = 14:00
Open_Time3  = 17:00
Close_Time3 = 18:00
Open_Time4  = 21:00
Close_Time4 = 22:00
MaxUser_BC1 = 10
MaxUser_BC7 = 10

A successful update results in a server running the new version with all player data intact. Reserve at least 30 minutes of GM testing before announcing the reopening — problems discovered with a full server are exponentially harder to resolve under player pressure.

Perguntas frequentes