How to demote the ad 2012 forest and domain levels

We know that the AD Active Directory cannot be demoted by default, for example, the level of 2003 raised to 2008 is an irreversible operation. However, in Windows Server 2008 R2 and Windows Server 2012, we can demote the forest level and domain level from 2012 to 2008r2, or demote to 2008 from 2008 R2. Of course, we can't drop it down to a lower level, like level 2003.

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We can use PowerShell to add the ad Management module, complete the following experiments.

1. Import the AD Management module

Import-module-name ActiveDirectory

2. Check the forest level of the ad

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Get-adforest | Format-table Name, Forestmode

3. We try to reduce the forest level and the domain level to the Windows2008 level.

Set-adforestmode–identity "appv.com" –forestmode windows2008forest

Set-addomainmode–identity "appv.com" –domainmode Windows2008domain

4. Let's use the command to see if the forest level and domain level are degraded to the Windows2008 level.

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Get-adforest | Format-table Name, Forestmode

Get-addomain | Format-table Name, Domainmode