# Validate Raise Domain and Forest Functional Levels in AD DS on Windows Server with AD/DNS evidence > Use Raise Domain and Forest Functional Levels in AD DS on Windows Server to review this narrow operational decision without extending the source beyond its stated scope. - Canonical URL: https://update.dsesecurity.com/updates/validate-raise-domain-and-forest-functional-levels-in-ad-ds-on-windows-server-with-ad-dns-evidence/ - Publisher: Detection Systems & Engineering (DSE Security) - Author: DSE Security Editorial Team - Published: 2026-08-27T17:06:39+00:00 - Modified: 2026-08-27T17:07:31+00:00 - Last reviewed by DSE: 2026-08-27 - Resource type: Checklist - DSE priority: Advisory - Topics: Cybersecurity, Microsoft 365 & Identity, Networks & Infrastructure - Reading time: 3 minutes ## What you need to know Use Raise Domain and Forest Functional Levels in AD DS on Windows Server to review this narrow operational decision without extending the source beyond its stated scope. ## Potentially affected Teams, systems, services, or facilities within the stated scope of Raise Domain and Forest Functional Levels in AD DS on Windows Server ## DSE recommendation Compare the observed state with the cited official source, document applicability and exceptions, and test any approved change with rollback safeguards. ## Article Treat this document as a focused evidence review: Validate Raise Domain and Forest Functional Levels in AD DS on Windows Server with AD/DNS evidence. Only the official source and traced locations below supply facts. Confirm applicability before acting. ## Source fact: The official [Raise Domain and Forest Functional Levels in AD DS on Windows Server](https://learn.microsoft.com/en-us/windows-server/identity/ad-ds/plan/raise-domain-forest-functional-levels) from Microsoft supports the following bounded statements: - At Introduction below H1, Microsoft states: “Functional levels determine the available Active Directory Domain Services (AD DS) domain or forest capabilities.” The research record locates this support at Introduction below H1. - At Introduction below H1, Microsoft states: “Functional levels also determine which Windows Server operating systems you can run on domain controllers in the domain or forest.” The research record locates this support at Introduction below H1. Do not import neighboring assumptions into the source record. The supported task is a scoped comparison involving forests, domains, controllers, directory partitions, trusts, sites, replication links, service accounts, and delegated roles and the conditions the source actually describes. ## What the source does not establish The cited page and retained statements do not establish the current state of any DSE or customer environment, prove that the documented configuration is applicable, or authorize a production change. Confirm supported versions, dependencies, and the current live source before use. No current deployment state or change approval follows from the source alone. Validate Windows DNS, time synchronization, network reachability, PKI, backups, virtualization safeguards, and privileged identity, and treat examples or options as conditional inputs rather than defaults. ## Applicability questions - For source statement 1 at Introduction below H1, which observable configuration, record, or test can confirm applicability here? - For source statement 2 at Introduction below H1, which observable configuration, record, or test can confirm applicability here? - Within forests, domains, controllers, directory partitions, trusts, sites, replication links, service accounts, and delegated roles, which versions, roles, and configuration states define the review population? - Could Windows DNS, time synchronization, network reachability, PKI, backups, virtualization safeguards, and privileged identity invalidate the test, hide a failure, or change applicability? - Who owns the decision, and which observation requires stopping, escalation, or rollback? ## DSE recommendation: DSE recommends using the cited source as the evidence anchor for this decision. Use a two-person review for the source interpretation and the resulting operational decision. Record the source location, examined part of forests, domains, controllers, directory partitions, trusts, sites, replication links, service accounts, and delegated roles, observed and expected states, owner, and reason for deviation. An implementation decision needs an owner, approved window, prechecks, observable outcome, stop authority, and rollback path. Validate Windows DNS, time synchronization, network reachability, PKI, backups, virtualization safeguards, and privileged identity before and after the test, and store only sanitized operational evidence. ## Verification and evidence Tie each conclusion back to Introduction below H1; Introduction below H1 and to observable material such as directory and policy exports, replication and locator tests, event logs, trust state, role ownership, and controlled authentication tests. Preserve provenance and stable identifiers without copying secrets into the evidence set. Label this evidence set DSE-20260827-047 so observations, approvals, exceptions, and later rechecks cannot be substituted from another source review. Retain the starting state, authorization, execution record, outcome, deviation, and final state as one review package. Move disruptive checks to an approved test path. Reopen the decision when versions, design, dependencies, ownership, or official guidance changes. ## Official references - [Raise Domain and Forest Functional Levels in AD DS on Windows Server](https://learn.microsoft.com/en-us/windows-server/identity/ad-ds/plan/raise-domain-forest-functional-levels) — Microsoft ## Primary reference - Name: Raise Domain and Forest Functional Levels in AD DS on Windows Server - Authority: Microsoft Learn - URL: https://learn.microsoft.com/en-us/windows-server/identity/ad-ds/plan/raise-domain-forest-functional-levels - Source publication date: Not stated by the source ## Citation and use Preferred citation: “Validate Raise Domain and Forest Functional Levels in AD DS on Windows Server with AD/DNS evidence,” DSE Security, https://update.dsesecurity.com/updates/validate-raise-domain-and-forest-functional-levels-in-ad-ds-on-windows-server-with-ad-dns-evidence/ Publishing principles: https://update.dsesecurity.com/updates/dse-updates-editorial-methodology/ Usage and citation policy: https://update.dsesecurity.com/usage/ Copyright © 2026 Detection Systems & Engineering. 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