Windows Server 2025 - What's New, Features & Benefits

For small businesses with up to 25 users and 50 devices.

• Licensing model: server licence without client access licences (CALs), usually available through hardware manufacturers (OEM).
• Virtualisation: A Hyper-V host with several virtual machines requires Standard or Datacenter. The exact usage rights are defined by Microsoft’s current licensing terms.

For physical servers and environments with few virtual machines.

• Licensing model: core-based, plus client access licences (CALs) per user or device; Remote Desktop Services require separate CALs.
• Virtualisation: up to two virtual operating system environments or Hyper-V containers per fully licensed host.

For highly virtualised environments and data centres.

• Licensing model: core-based, plus CALs per user or device.
• Virtualisation: unlimited virtual machines and Hyper-V containers per fully licensed host.
• Datacenter only: among others Storage Spaces Direct and the Network Controller for software-defined networking.

Hyper-V supports up to 4 petabytes of memory and 2,048 logical processors per host, and up to 240 TB of memory and 2,048 virtual processors per generation 2 VM.

• GPU partitioning (GPU-P): a physical GPU is shared between several VMs, with live migration and high availability in a cluster.
• Dynamic processor compatibility: simplifies live migration between hosts with different processor generations.
• Workgroup clusters: Hyper-V clusters without an Active Directory domain, including live migration.

Several protections are enabled by default or are new.

• Credential Guard: enabled by default on suitable hardware.
• SMB hardening: SMB signing required by default for outbound connections, rate limiting of failed authentication attempts, NTLM for SMB can be blocked.
• Delegated Managed Service Accounts (dMSA): replace classic service accounts with managed, randomly generated keys.
• Windows LAPS: extended management of local administrator passwords.

A new functional level with an optional 32k database page size. It raises earlier limits considerably, for example the number of values in multivalued attributes. The switch requires all domain controllers in the forest to support the new format.

• NVMe: optimised performance with more IOPS and lower CPU utilisation.
• ReFS: native deduplication and compression, plus block cloning.
• Storage Spaces Direct: thin provisioning of volumes.
• Storage Replica: compression and Enhanced Log for faster replication.

Encrypted file access over QUIC was previously limited to Datacenter: Azure Edition and is now also available in Standard and Datacenter, for example for remote access without a classic VPN.

• Network ATC: configures host networking for Windows Server clusters based on intents. Administrators define what an adapter is used for (management, compute or storage); Network ATC applies the configuration automatically and prevents drift between nodes.
• Software-defined networking: the Network Controller runs directly as a cluster service on the hosts; additions include tag-based segmentation, default network policies and SDN Multisite.
• Accelerated Networking (preview): simplifies SR-IOV for VMs in a cluster.

• In-place upgrade: directly from Windows Server 2012 R2 and later, i.e. up to four versions at once.
• User interface: Windows 11-style desktop, Windows Terminal and WinGet preinstalled; Bluetooth and Wi-Fi can be used.

Security updates are applied to running memory without a restart. For Windows Server 2025 Standard and Datacenter this is available through Azure Arc, according to Microsoft now at no extra cost. The roughly quarterly baseline updates still require a restart.

• Azure Arc Setup: the wizard for connecting to Azure Arc is preinstalled.
• Windows Server Management enabled by Azure Arc: for licences with Software Assurance or subscription licences, this includes Windows Admin Center in the Azure portal, Azure Update Manager and best practices assessments.

Microsoft’s hyperconverged infrastructure platform is now called Azure Local. It is a separate product billed through Azure with Azure Arc as its control plane and is not part of Windows Server 2025. Several capabilities from this platform, such as Network ATC, thin provisioning and ReFS deduplication, are now also available in Windows Server 2025.

Container images can be moved between hosts and environments without modification (portability).

WSL can be set up on Windows Server 2025 with the command wsl.exe --install, including on Server Core. The command enables the required components, downloads the Linux kernel and sets WSL 2 as the default. There is no “WSL 3”.

Secured-core combines hardware, firmware and operating system protection. Requirements include TPM 2.0, Secure Boot, virtualisation-based security (VBS), DMA protection and DRTM. New in Windows Server 2025 is hypervisor-enforced paging translation (HVPT), which is enabled by default on supported hardware.

Minimum requirements according to Microsoft; individual roles need considerably more resources.

• Processor: 64-bit, 1.4 GHz, with support for NX/DEP, CMPXCHG16b, LAHF/SAHF, PrefetchW, SLAT (EPT/NPT), SSE4.2 and POPCNT.
• Memory: at least 2 GB (Server Core and Desktop Experience), 4 GB recommended for Desktop Experience; ECC for physical hosts.
• Storage: at least 32 GB for the system partition.
• Network: Ethernet adapter with at least 1 Gbit/s.
• Only for certain features: UEFI 2.3.1c with Secure Boot and TPM 2.0, for example for BitLocker or Secured-core.

The recommended method for a clean foundation. The existing OS will be overwritten.

• Data Backup: Back up all important data and settings.
• Installation Medium: Create a bootable medium (USB/DVD).
• Booting & Installation: Start from the medium, follow the wizard, select edition.
• Post-Installation: Install drivers, Windows Update, configure Roles/Features, restore data/apps.

Updates an existing system while keeping data and settings.

• Supported paths: directly from Windows Server 2012 R2, 2016, 2019 and 2022.
• Compatibility check and backup: always carry these out first.
• Start the upgrade: run setup from the running system and choose the upgrade option.
• Follow-up: check applications and services, install updates.

Note: For some roles, such as domain controllers, a clean installation followed by role migration is often the cleaner approach.

• Backup: Before every migration or installation, a full backup is essential!
• Compatibility: Check the compatibility of your applications and services.
• Test Environment: Ideally, perform migrations in a test environment first.