Windows Server 2025 adds hotpatching for on-premises servers through Azure Arc, a major Active Directory update, SMB over QUIC in Standard and Datacenter, GPU partitioning with live migration, much larger Hyper-V limits and a faster NVMe storage stack. Windows Server 2022 leaves mainstream support in October 2026, so new deployments should start on 2025.
Written by the Softkeyworld technical team · Updated October 2026
Windows Server 2025 became generally available on 1 November 2024 and has had nearly two years of cumulative updates since. Windows Server 2022 is still a solid, fully patched platform, but its mainstream support phase ends this month. If you are planning a new host, refreshing hardware or deciding whether to upgrade domain controllers, the question is no longer whether 2025 is ready. It is which of its changes matter to your environment.
Below we go through the differences that actually change how servers are run, using Microsoft's own What's new in Windows Server 2025 documentation as the baseline, then look at who should upgrade and which edition to choose.
Key takeaways
- Hotpatching cuts planned security reboots to roughly four a year on Arc-connected Server 2025 Standard and Datacenter.
- Active Directory gains functional level 10, an optional 32k database page size and NUMA awareness.
- SMB over QUIC is no longer limited to Azure Edition.
- Server 2022 mainstream support ends 14 October 2026; Server 2025 mainstream runs to 14 November 2029.
Windows Server 2025 vs 2022 at a glance
| Area | Windows Server 2022 | Windows Server 2025 |
|---|---|---|
| General availability | 18 August 2021 | 1 November 2024 |
| Mainstream support ends | 14 October 2026 | 14 November 2029 |
| Extended support ends | 15 October 2031 | 15 November 2034 |
| Hotpatching (on-premises) | Datacenter: Azure Edition only | Standard and Datacenter via Azure Arc |
| SMB over QUIC server | Datacenter: Azure Edition only | Standard, Datacenter and Azure Edition |
| AD functional level | 2016 (level 7) remained the highest | New level 10, 32k page size option |
| GPU sharing for VMs | Discrete Device Assignment (whole GPU) | GPU partitioning with live migration and failover |
| Max memory per Gen 2 VM | 24 TB | 240 TB |
| Max host memory | 48 TB | 4 PB (with 5-level paging) |
| Credential Guard | Off by default | On by default on capable hardware |
Lifecycle dates are taken from Microsoft's Windows Server 2025 lifecycle page and its 2022 equivalent. Hyper-V figures come from Microsoft's published Hyper-V scale limits.
Hotpatching: fewer reboots for on-premises servers
Hotpatching patches the in-memory code of running processes, so a security update takes effect without a restart. In Server 2022, this was limited to Datacenter: Azure Edition running in Azure. In Server 2025, physical and virtual machines running Standard or Datacenter can use it once they are connected to Azure Arc.
The cycle works on quarters. A normal cumulative update installs as a "baseline" in January, April, July and October and needs a reboot. The two months after each baseline deliver hotpatches that do not. According to Microsoft's Hotpatch documentation, that works out at around four planned restarts a year instead of twelve. Microsoft may also issue an unplanned baseline for a critical zero-day.
What hotpatching requires
- Windows Server 2025 Standard or Datacenter, build 26100.1742 or later, Desktop Experience or Server Core.
- Virtualisation-based security support: UEFI with Secure Boot, which means Generation 2 for Hyper-V VMs.
- An Azure subscription and the Azure Connected Machine (Arc) agent, with Hotpatch enabled in the Arc portal.
The commercial terms have changed since launch. When hotpatching for Arc-connected servers became generally available in July 2025, it was a paid per-core subscription. Microsoft has since announced that Arc-enabled hotpatching for Server 2025 is available at no extra cost. Check the current terms on Microsoft's page before you plan around it. Hotpatches cover security updates only: .NET, driver, firmware and non-security updates still need a restart.
Active Directory: the first big change in years
Server 2019 and 2022 introduced no new domain or forest functional level. Server 2025 adds level 10, and with it several long-awaited changes:
- 32k database page size (optional). Since Windows 2000, the AD database has used 8k pages. 32k pages let single objects grow far larger, and multi-valued attributes can hold around 3,200 values. Enabling it is forest-wide and one-way, and every DC must run Server 2025.
- NUMA awareness. AD DS can now use processors across all processor groups instead of only group 0, so large DCs can scale beyond 64 cores.
- Security defaults. LDAP supports TLS 1.3, new deployments require LDAP signing and sealing, and the KDC no longer issues RC4 TGTs. Legacy SAM RPC password-change methods are blocked remotely by default.
- Delegated Managed Service Accounts (dMSA). These replace traditional service accounts with machine-bound, randomised keys, and the old account's password is disabled after migration.
You can add Server 2025 DCs to an existing domain running an older functional level and raise it later, once every DC is on 2025. Test application compatibility first, especially anything still relying on RC4 or legacy password-change calls. Those are the issues we see surface after DC upgrades.
SMB over QUIC and SMB hardening
SMB over QUIC tunnels file sharing through TLS 1.3 on UDP port 443. Remote users can reach a file server securely without a VPN. In 2022 it required Azure Edition. In 2025 it is available in Standard and Datacenter, along with client access control based on certificates.
Server 2025 also tightens SMB defaults: signing is required for all outbound connections, NTLM can be blocked for outbound SMB, an authentication rate limiter slows brute-force attempts, and the default firewall group no longer opens NetBIOS ports 137 to 139. Older NAS devices that cannot sign SMB traffic are the most frequent casualty, so audit them before rollout.
Hyper-V: GPU partitioning and bigger VMs
With GPU partitioning (GPU-P), one physical GPU can be divided into fractions assigned to several VMs. Unlike Discrete Device Assignment in 2022, these VMs can live-migrate between hosts and fail over in a cluster. That makes GPU-accelerated VDI or inference workloads practical without pinning them to one server. Check that your GPU and driver are on the supported list.
Scale limits jump as well: up to 240 TB of memory and 2,048 virtual processors per Generation 2 VM, and up to 4 PB of host memory with 5-level paging. Hyper-V Manager now creates Generation 2 VMs by default. Workgroup clusters (Hyper-V failover clusters without Active Directory) also arrive, which suits branch sites and edge deployments.
NVMe storage performance
Microsoft reworked the storage stack in Server 2025 to cut overhead on NVMe drives. A later cumulative update added an opt-in native NVMe I/O path that removes the legacy SCSI translation layer. It is not on by default and is enabled through a registry or Group Policy setting. Microsoft's own tests on high-end PCIe 5.0 hardware reported up to around 80% more IOPS and up to around 45% lower CPU use under heavy load. Treat these as best-case lab figures and benchmark your own workload before and after enabling the feature.
Other changes worth knowing
- Credential Guard on by default on hardware that supports VBS.
- OpenSSH Server installed by default, enabled in one click from Server Manager.
- Windows LAPS improvements, including passphrases and image-rollback detection.
- Pay-as-you-go licensing through Azure Arc as an alternative to perpetual licences.
- Windows 11-style desktop on Desktop Experience installs, plus DTrace for performance tracing.
Standard vs Datacenter in Windows Server 2025
Both editions are licensed per physical core, with a minimum of 8 cores per processor and 16 per server, plus Client Access Licences (CALs) for users or devices. The difference is virtualisation rights and a handful of datacentre features:
| Capability | Standard | Datacenter |
|---|---|---|
| Windows Server VMs per fully licensed host | 2 (stack licences for more) | Unlimited |
| Hotpatching via Azure Arc | Yes | Yes |
| SMB over QUIC | Yes | Yes |
| Storage Spaces Direct | No | Yes |
| Software-defined networking | No | Yes |
| Storage Replica | Limited (single partnership and volume) | Full |
For a physical server or a host with one or two Windows VMs, Windows Server 2025 Standard is the usual choice. Hosts running many Windows VMs, or clusters using Storage Spaces Direct, are better served by Windows Server 2025 Datacenter. The trade-offs are the same as in the previous release, which we cover in more depth in Windows Server 2022 Standard vs Datacenter.
Who should upgrade, and who can wait?
- Upgrade now: new hardware, new domain controllers, Hyper-V hosts that need GPU sharing or larger VMs, and anyone who wants fewer patch reboots or VPN-less file access.
- Plan within the next year or two: stable Server 2022 file, print and application servers. They still receive security updates until October 2031, but no new features or non-security fixes after mainstream ends.
- Stay on 2022 for now: line-of-business applications whose vendors have not yet certified Server 2025, and environments with legacy devices that cannot handle the new SMB or LDAP defaults.
Microsoft supports in-place upgrades to Server 2025 from Windows Server 2012 R2 and later. For domain controllers and hosts, though, we still recommend building fresh and migrating roles. Our Windows Server 2025 download, install and activation guide walks through a clean build. If you are standardising on 2022 for compatibility reasons, Windows Server 2022 Standard remains a supported option.
Pre-upgrade checklist: moving from 2022 to 2025
Since Server 2025, non-clustered systems can upgrade up to four versions at a time, according to Microsoft's Windows Server upgrade overview. Clusters still move one version at a time using a rolling upgrade. Whichever route you take, work through these steps first:
- Take a full backup and test the restore. A snapshot is not a backup for domain controllers. Use a system-state-aware backup.
-
Inventory roles and agents with
Get-WindowsFeature | Where Installed. Confirm backup, antivirus and monitoring vendors support Server 2025. - Check firmware for VBS readiness. UEFI, Secure Boot and TPM 2.0 are needed for Credential Guard and hotpatching, and old BIOS-mode installs will miss out.
- Audit SMB and LDAP clients. Look for devices that cannot sign SMB traffic, applications using LDAP without signing, and services still requesting RC4 Kerberos tickets.
- Confirm licensing. You need a Server 2025 key for the same edition (Standard or Datacenter), enough core licences for the hardware, and Server 2025 CALs.
-
Run setup.exe from mounted media, choose "Keep files, settings and apps", then run
slmgr /dlvafterwards to verify activation.
For domain controllers, the cleaner route is still to promote a new Server 2025 DC, transfer FSMO roles, and demote the old one. That avoids carrying years of accumulated configuration into the new OS.
Frequently asked questions
When does Windows Server 2022 support end?
Mainstream support ends on 14 October 2026 and extended support, which covers security updates only, ends on 15 October 2031.
Is Windows Server 2025 stable enough for production?
Yes. It has been generally available since November 2024 with almost two years of cumulative updates. As with any release, test critical applications and backup agents before migrating.
Does hotpatching work without Azure?
On-premises Server 2025 Standard and Datacenter need to be connected to Azure Arc for hotpatching. The server still runs locally; Arc is used for enrolment and update orchestration.
Can I upgrade Server 2022 to 2025 in place?
Yes. Run setup.exe from the Server 2025 media and keep files, settings and apps. Back up first, check role compatibility, and use a key for the matching edition.
Do I need new CALs for Server 2025?
Yes. CALs must be the same version as, or newer than, the server they access. Server 2022 CALs do not cover users or devices accessing a Server 2025 machine.
Is SMB over QUIC available in Standard edition?
Yes. From Windows Server 2025 it is included in Standard and Datacenter, not just Datacenter: Azure Edition.
Our recommendation
For any new server or hardware refresh, start on Windows Server 2025. It is supported into 2034, it is easier to patch, and the security defaults are better. Most small and mid-sized businesses running a single physical server or a couple of VMs will find Standard edition covers everything they need. Keep 2022 where an application vendor requires it, and plan those moves before extended support becomes your only safety net.
Get Windows Server 2025 Standard
Related reading
| Resource | Why read it |
|---|---|
| Windows Server 2025 install and activation guide | Step-by-step clean build and activation |
| Server Standard vs Datacenter explained | Deeper look at virtualisation rights and edition choice |
| Windows Server 2025 Datacenter | For dense virtualisation hosts and S2D clusters |