AD domain and forest functional levels
Microsoft's edit ·
Microsoft's commit message in MicrosoftDocs/windowsserverdocs · commit 69c9510 · +15 −17 lines · also on GitHub
⋯ 7 unchanged lines
88
---
99
# Raise domain and forest functional levels in Active Directory Domain Services
1010
11
−>Applies to: Windows Server 2025 (preview), Windows Server 2022, Windows Server 2019, Windows Server 2016, Windows Server 2012
11
+>Applies to: Windows Server 2025 (preview), Windows Server 2022, Windows Server 2019, Windows Server 2016
1212
1313
> [!IMPORTANT]
1414
> Windows Server 2025 is in PREVIEW. This information relates to a prerelease product that may be substantially modified before it's released. Microsoft makes no warranties, expressed or implied, with respect to the information provided here.
1515
16
−Functional levels determine the available Active Directory Domain Services (AD DS) domain or forest capabilities. They also determine which Windows Server operating systems you can run on domain controllers in the domain or forest. Level changes happen when you use later versions of your domain controller operating system, the domain, or your forest functional level. This article describes how to raise Active Directory domain and forest functional levels in Microsoft Windows Server domain controllers. We recommend you upgrade Active Directory and Active Directory Lightweight Directory Services servers to the latest release.
17
−
18
−To activate the latest domain features, all domain controllers in the domain must run the latest version of Windows Server. If they don't meet this requirement, the administrator can't raise the domain functional level.
16
+Functional levels determine the available Active Directory Domain Services (AD DS) domain or forest capabilities. Functional levels also determine which Windows Server operating systems you can run on domain controllers in the domain or forest. Level changes happen when you use later versions of your domain controller operating system, the domain, or your forest functional level. This article describes how to raise Active Directory domain and forest functional levels. We recommend you upgrade Active Directory Domain Service servers to the latest release.
1917
20
−To activate the latest forest-wide features, all domain controllers in the forest must run the Windows Server operating system version that matches the desired forest functional level. The current domain functional level must also already be at the latest level. If the forest meets these requirements, the administrator can raise the forest functional level.
18
+To activate the latest domain features, all domain controllers in the domain must run the version of Windows Server that matches or is newer than the desired functional level. If they don't meet this requirement, the administrator can't raise the domain functional level.
2119
22
−> [!WARNING]
23
−> Changes to the domain and forest functional levels are irreversible. In order to undo the change, you must perform a forest recovery to revert to an earlier point of time.
20
+To activate the latest forest-wide features, all domain controllers in the forest must run the Windows Server operating system version that matches or is newer than the desired functional level. The current domain functional level must already be at the latest level. If the forest meets these requirements, the administrator can raise the forest functional level.
2421
22
+TODO:
2523
The domain and forest functional levels only affect how the domain controllers operate together as a group. The clients that interact with the domain or with the forest are unaffected by the changes. Applications are also unaffected by these changes. However, applications can use new features found in later versions of Windows Server once the administrator raises the domain level. For more information about the functional levels, see [Active Directory Domain Services functional levels](/windows-server/identity/ad-ds/active-directory-functional-levels).
2624
25
+> [!WARNING]
26
+> Changes to the domain and forest functional levels are irreversible. In order to undo the change, you must perform a forest recovery to revert to an earlier point in time.
27
+
2728
## Prerequisites
2829
29
−You need to complete the following things to raise the domain functional level in Windows Server:
30
+You need to complete the following things to raise the domain functional level:
3031
3132
- All domain controllers in the domain are running at least the version of Windows Server that you want to raise the domain functional level to. For example, to raise the domain functional level to Windows Server 2025, all domain controllers in the domain must be running Windows Server 2025. If you have domain controllers running earlier versions of Windows Server, you must upgrade them to Windows Server 2025 before you can raise the domain functional level.
3233
33
−- Before you can promote a machine running Windows Server 2025 to a domain controller in an existing domain, that domain must also be at least at the Windows Server 2016 functional level. For newly created Active Directory forests under Windows Server 2025, the minimum functional level is Windows Server 2016. Earlier versions of Windows Server don't support Windows Server 2025 domain controllers.
34
+- Before you can promote a machine running Windows Server 2025 to a domain controller in an existing domain, that domain must also be at least at the Windows Server 2016 functional level. Earlier versions of Windows Server don't support Windows Server 2025 domain controllers.
3435
3536
- Your Active Directory forest and domain is operational and free from replication errors. To learn more about replication errors, see [Diagnose Active Directory replication failures](/troubleshoot/windows-server/active-directory/diagnose-replication-failures).
3637
37
−- Identify all your DCs hosting the Global Catalog (GC) and FSMO roles. Create and verify backups of these Active Directory Domain Services domain controllers before making changes.
38
+- Identify all your DCs hosting the Global Catalog (GC) and FSMO roles. Create and verify backups of these domain controllers before making changes.
3839
3940
- You must be a member of the Enterprise Admins group or equivalent to raise the forest functional level.
4041
⋯ 5 unchanged lines
4647
4748
- Active Directory module for Windows PowerShell.
4849
49
−> [!NOTE]
50
−> Before you can promote a machine running Windows Server 2025 to a domain controller in an existing domain, that domain must also be at least at the Windows Server 2016 functional level.
51
−
5250
## View the current functional level
5351
5452
To view the current domain and forest functional levels, you can use the Active Directory Domains and Trusts console or Windows PowerShell. The following sections describe how to raise the functional levels using these methods.
⋯ 5 unchanged lines
6058
6159
To raise the domain or forest functional level using the Active Directory Domains and Trusts console, follow these steps.
6260
63
−1. Sign on to a computer with the AD DS Remote Server Administration Tools (RSAT) installed.
61
+1. Sign in to a computer with the AD DS Remote Server Administration Tools (RSAT) installed.
6462
6563
1. Select the Start menu, then enter _Active Directory Domains and Trusts_ in the search box.
6664
⋯ 7 unchanged lines
7472
7573
To view the domain or forest functional level using PowerShell, follow these steps.
7674
77
−1. Sign on to a computer with the AD DS Remote Server Administration Tools (RSAT) installed.
75
+1. Sign in to a computer with the AD DS Remote Server Administration Tools (RSAT) installed.
7876
7977
1. Open PowerShell as an administrator.
8078
⋯ 24 unchanged lines
105103
106104
To raise the domain or forest functional level using the Active Directory Domains and Trusts console, follow these steps.
107105
108
−1. Sign on to a computer with the AD DS Remote Server Administration Tools (RSAT) installed.
106
+1. Sign in to a computer with the AD DS Remote Server Administration Tools (RSAT) installed.
109107
110108
1. Select the Start menu, then enter _Active Directory Domains and Trusts_ in the search box.
111109
⋯ 15 unchanged lines
127125
128126
To raise the domain or forest functional level using PowerShell, follow these steps.
129127
130
−1. Sign on to a computer with the AD DS Remote Server Administration Tools (RSAT) installed.
128
+1. Sign in to a computer with the AD DS Remote Server Administration Tools (RSAT) installed.
131129
132130
1. Open PowerShell as an administrator.
133131
⋯ 25 unchanged lines
Microsoft's Markdown source from MicrosoftDocs/windowsserverdocs, © Microsoft Corporation, under CC BY 4.0. Changed lines with up to 3 unchanged lines around each; ChangeIntel kept this copy 10 Oct 02:30 UTC. The commit date is when the source changed, which can be hours or days before Learn published it.