<DoNotAutoUpgrade>true</DoNotAutoUpgrade>

It works fine in ImprovementDefs, same way as in Trade Resource Defs

  ImprovementDefs.xml(319,17): error:
element 'DoNotAutoUpgrade' is not allowed for content model '(InternalName,DisplayName,ShortDescription,Description?,Icon,BuildIcon?,ListIcon?,ImprovementType,ResourceStatType?,SecondaryType?,PlacementType?,SupportedPlanetTraits*,RelativeWeight?,OnePerPlanet?,IsIndestructible?,IsGalacticWonder?,IsPlayerWonder?,IsColonyUnique?,DoNotAutoUpgrade?,UnderPopulationCapOnly?,DoNotShowNotificationsWhenBuilt?,CapitalOnly?,LandPercentageMin?,Stats*,Triggers*,LevelEffectStats*,LevelEffectTriggers*,NeighborBonuses*,Prerequ?,Preclusions?)'

<Improvement>
    <InternalName>ColonyCapitalUpgrade</InternalName>
    <DisplayName>ColonyCapitalUpgrade_Name</DisplayName>
    <ShortDescription>ColonyCapitalUpgrade_ShortDec</ShortDescription>
    <Description>ColonyCapitalUpgrade_Dec</Description>
    <Icon>ColonyCapital.png</Icon>
    <BuildIcon>ColonyCapital_Build.png</BuildIcon>
    <ListIcon>ColonyCapital_Icon.png</ListIcon>
    <ImprovementType>Special</ImprovementType>
    <SecondaryType>MaxManufacturing</SecondaryType>
    <PlacementType>Manufacturing</PlacementType>
    <IsIndestructible>true</IsIndestructible>
    <IsColonyUnique>true</IsColonyUnique>
    <Stats>
      <EffectType>ResistanceBonus</EffectType>
      <Target>
        <TargetType>Colony</TargetType>
      </Target>
      <BonusType>Flat</BonusType>
      <Value>0.1</Value>
    </Stats>
    <Stats>
      <EffectType>ProductionPoints</EffectType>
      <Target>
        <TargetType>Colony</TargetType>
      </Target>
      <BonusType>Flat</BonusType>
      <Value>1</Value>
    </Stats>
    <Stats>
      <EffectType>GoodsAndServices</EffectType>
      <Target>
        <TargetType>Colony</TargetType>
      </Target>
      <BonusType>Flat</BonusType>
      <Value>3</Value>
    </Stats>
    <Stats>
      <EffectType>InfluencePerTurn</EffectType>
      <Target>
        <TargetType>Colony</TargetType>
      </Target>
      <BonusType>Flat</BonusType>
      <Value>1</Value>
    </Stats>
    <Stats>
      <EffectType>PopulationCap</EffectType>
      <Target>
        <TargetType>Colony</TargetType>
      </Target>
      <BonusType>Flat</BonusType>
      <Value>4</Value>
    </Stats>
    <Stats>
      <EffectType>SensorPower</EffectType>
      <Target>
        <TargetType>Colony</TargetType>
      </Target>
      <BonusType>Flat</BonusType>
      <Value>16</Value>
    </Stats>
    <Stats>
      <EffectType>Maintenance</EffectType>
      <Target>
        <TargetType>Improvement</TargetType>
      </Target>
      <BonusType>Flat</BonusType>
      <Value>3</Value>
    </Stats>
    <Stats>
      <EffectType>ManufacturingCost</EffectType>
      <Scope>Queue</Scope>
      <Target>
        <TargetType>Improvement</TargetType>
      </Target>
      <BonusType>Flat</BonusType>
      <Value>100</Value>
    </Stats>
    <NeighborBonuses>
      <GiveBonusToNeighborType>Research</GiveBonusToNeighborType>
      <NeighborBonusValue>1</NeighborBonusValue>
    </NeighborBonuses>
    <NeighborBonuses>
      <GiveBonusToNeighborType>Wealth</GiveBonusToNeighborType>
      <NeighborBonusValue>1</NeighborBonusValue>
    </NeighborBonuses>
    <NeighborBonuses>
      <GiveBonusToNeighborType>Approval</GiveBonusToNeighborType>
      <NeighborBonusValue>1</NeighborBonusValue>
    </NeighborBonuses>
    <NeighborBonuses>
      <GiveBonusToNeighborType>MaxManufacturing</GiveBonusToNeighborType>
      <NeighborBonusValue>1</NeighborBonusValue>
    </NeighborBonuses>
    <NeighborBonuses>
      <GiveBonusToNeighborType>Influence</GiveBonusToNeighborType>
      <NeighborBonusValue>1</NeighborBonusValue>
    </NeighborBonuses>
    <NeighborBonuses>
      <GiveBonusToNeighborType>Population</GiveBonusToNeighborType>
      <NeighborBonusValue>1</NeighborBonusValue>
    </NeighborBonuses>
    <Prerequ>
      <Techs>
        <Option>XenoAdaptationTech</Option>
      </Techs>
      <UpgradesFrom>ColonyCapital</UpgradesFrom>
    </Prerequ>
    <DoNotAutoUpgrade>true</DoNotAutoUpgrade>
  </Improvement>

Is this wrong?

Oof, order does matter.

Will make mod maintenance a pain.

Logged this in Jira for one of the designers to take a closer look at.

Yes order matters....alot.

And mod Maintenace is not that much of a pain.

Thanks!  I noticed lots of posts about this through google so looked to modding instead of a suggestion.

On some of those they suggested a "global governor" to be the default settings on new colonies or a way to mass apply.

Quoting Horemvore, reply 5

Yes order matters....alot.

And mod Maintenace is not that much of a pain.

Was hoping to quick search and replace when it updates - should still be possible but will have to write a regular expression to place it since the properties around it are optional.

The schema files are used completely for documentation right?  Or can I set a different default in there?

They are not pure documentation, editing them usually ends wth a hard crash. That tells me they do more.