ArmA Reforger guide

Arma Reforger missionHeader: Time, Weather, XP and Conflict Settings

By the ChicagoServers team · Updated November 15, 2026 · 8 min read

The missionHeader block inside gameProperties in an Arma Reforger server config overrides parts of the scenario's mission header, so you can change things like the starting time, weather, XP multiplier and Conflict supply amounts without making a custom scenario. The Bohemia wiki confirms the block exists and shows it overriding the campaign mission header with fields such as m_iPlayerCount.

This guide lists the keys that two community references agree on, groups them by purpose, and gives an example. The key names come from community documentation, because Bohemia's page lists only the block and an example, so treat any key as something to test on your server after a game update. On ChicagoServers you edit it on the Configs tab under Server config.

Quick answer

Put the keys inside gameProperties.missionHeader in Server config on the Configs tab, then Save and Restart.
For time and weather overrides, set m_bOverrideScenarioTimeAndWeather to true, or the time and weather keys may be ignored.
m_bRandomStartingDaytime randomises the start time and overrides the hour and minute keys.
The Conflict keys, such as m_iStartingHQSupplies, only apply to the Conflict scenarios. A value of -1 is documented as the default.
The file must be valid JSON. One missing comma stops the server from reading it.

On this page

Where missionHeader goes
General keys
Time and weather keys
Saving keys
Conflict keys
A complete example
Problems and fixes
Frequently asked questions

Where missionHeader goes

missionHeader sits inside gameProperties, next to settings such as battlEye and serverMaxViewDistance. Everything inside it is optional, and anything you leave out keeps the scenario's own value.

Back up the config
On the Backups tab, choose World and settings and click Back up now.
Open Server config
Go to the Configs tab, pick Server config and switch to the Text view.

Add the block

Find the gameProperties block and add missionHeader inside it. Check the commas.

"gameProperties": {
  "missionHeader": {
    "m_sName": "My Server",
    "m_sDetails": "No teamkilling.",
    "m_bOverrideScenarioTimeAndWeather": true,
    "m_iStartingHours": 7,
    "m_iStartingMinutes": 30,
    "m_bRandomStartingWeather": true
  }
}

Save and restart
Click Save, then Restart. Read the Console tab for errors.

General keys

Key	Type	What it does
`m_sName`	text	Scenario name shown to players.
`m_sAuthor`	text	Scenario author.
`m_sDescription`	text	Short description.
`m_sDetails`	text	Longer description, which is a good place for your server rules.
`m_iPlayerCount`	number	Expected player count for the scenario.
`m_fXpMultiplier`	number	XP multiplier. 1 is the documented default.
`m_bMapMarkerEnableDeleteByAnyone`	true/false	Lets any player in a faction delete map markers, not just the one who placed them.
`m_iMapMarkerLimitPerPlayer`	number	Maximum map markers per player.

Time and weather keys

Key	Type	What it does
`m_bOverrideScenarioTimeAndWeather`	true/false	Must be `true` for the time and weather keys to apply.
`m_iStartingHours`	number	Start hour, 0 to 23.
`m_iStartingMinutes`	number	Start minute, 0 to 59.
`m_bRandomStartingDaytime`	true/false	Random start time. Overrides the hour and minute keys.
`m_fDayTimeAcceleration`	number	Daytime speed. 1 is real time and 2 is twice as fast.
`m_fNightTimeAcceleration`	number	Nighttime speed.
`m_bRandomStartingWeather`	true/false	Random weather at start.
`m_bRandomWeatherChanges`	true/false	Weather changes during play.

A common setup is a fixed morning start with a faster night, for example m_iStartingHours 7 and m_fNightTimeAcceleration 4, so players are not stuck in a long dark. Test your values with a client, since the scenario controls how time is shown.

Saving keys

Key	Type	What it does
`m_bIsSavingEnabled`	true/false	Enables saving of the scenario state.
`m_sSaveFileName`	text	Save file name. If it is not set, the world file name is used.

Conflict keys

These only apply to the Conflict scenarios. Community documentation lists -1 as the default for the first three.

Key	Type	What it does
`m_iControlPointsCap`	number	Control points needed to win.
`m_fVictoryTimeout`	number	Seconds a point must be held to win.
`m_iStartingHQSupplies`	number	Starting supplies at the main HQ.
`m_iMinimumBaseSupplies`	number	Minimum starting supplies for small bases.
`m_iMaximumBaseSupplies`	number	Maximum starting supplies for small bases.
`m_bIgnoreMinimumVehicleRank`	true/false	Removes rank requirements for spawning vehicles.
`m_fSupplyOffloadAssistanceReward`	number	XP share for helping unload supplies. Listed in one reference only.

See the scenarios guide for the Conflict scenario IDs.

A complete example

Inside gameProperties. Keep your other keys in the block.

"missionHeader": {
  "m_sName": "Chicago Conflict",
  "m_sDetails": "Be respectful. No teamkilling.",
  "m_iPlayerCount": 40,
  "m_bOverrideScenarioTimeAndWeather": true,
  "m_iStartingHours": 7,
  "m_iStartingMinutes": 30,
  "m_fNightTimeAcceleration": 4,
  "m_bRandomStartingWeather": true,
  "m_bRandomWeatherChanges": true,
  "m_fXpMultiplier": 1.5,
  "m_iMapMarkerLimitPerPlayer": 20
}

Change one group of settings at a time. If the server stops loading, restore the backup you took, or remove the block you added.

Problems and fixes

What you see	Likely cause
The server will not start	Invalid JSON: a missing comma or quote, or a duplicate `gameProperties` block. Fix it on the Configs tab and read the Console tab.
Time or weather is unchanged	`m_bOverrideScenarioTimeAndWeather` is not `true`.
The start hour is ignored	`m_bRandomStartingDaytime` is on and overrides it.
Conflict settings do nothing	You are not running a Conflict scenario.
A key has no effect	It may not apply to your scenario or game version. Test it, and check the server config guide.
Settings are not saved	Click Save, then Restart.

Hosting a Game Master mission instead? See the Game Master guide. Looking for a host? See Arma Reforger server hosting.

Frequently asked questions

What is missionHeader in Arma Reforger?

A block inside gameProperties in the server config that overrides parts of the scenario's mission header, so you can change time, weather, XP and Conflict settings without a custom scenario.

How do I set the starting time on an Arma Reforger server?

Set m_bOverrideScenarioTimeAndWeather to true, then set m_iStartingHours and m_iStartingMinutes inside missionHeader. m_bRandomStartingDaytime overrides them if it is on.

How do I change the XP rate in Arma Reforger?

Set m_fXpMultiplier inside missionHeader. 1 is the documented default.

Do the Conflict missionHeader settings work on every scenario?

No. The supply, victory and vehicle rank keys only apply to the Conflict scenarios.

Why is my missionHeader being ignored?

Common causes are invalid JSON, a second gameProperties block, not restarting after saving, or time and weather keys used without m_bOverrideScenarioTimeAndWeather set to true.