Extended support for Windows Server 2008 R2 and Windows Server 2008 ended in January 2020. Extended Security Updates (ESU) are available, with one option to migrate your on-premises servers to Azure, where you can continue to run them on virtual machines. To find out more, see Extended Security Updates overview.
A clean install, where you install a blank server or overwrite an existing operating system (OS), is the simplest way to install Windows Server. However, before you can do a clean install, you must back up your data and plan for how to reinstall your original applications. You should also make sure your system meets the hardware requirements for Windows Server.
In-place upgrades let you upgrade to a later version of Windows Server while keeping your original settings, server roles, features, and data. You can upgrade between up to two Server versions at a time. For more information, see Which version of Windows Server should I upgrade to?. Keep in mind that some roles and features don't support in-place upgrades. In-place upgrades work best with virtual machines (VMs) that don't need specific Original Equipment Manufacturer (OEM) hardware drivers to upgrade successfully.
For more detailed guides for how to upgrade for different versions of Windows Server, including information about which roles and features support in-place upgrades, see Upgrade and migrate roles and features in Windows Server.
The Cluster operating system rolling upgrade gives an administrator the ability to upgrade the operating system of the cluster nodes without stopping the Hyper-V or the Scale-Out File Server workloads. For example, if nodes in your clusters are running an earlier version of Windows Server, your admin can use a rolling upgrade to install a later version on them without having to turn off the cluster, which would otherwise affect Service Level Agreements. For more information, see Cluster OS rolling upgrade.
Migration is when you move roles or features from a source computer running Windows Server to a destination computer that's also running Windows Server. This process is gradual, moving one role or feature at a time, without upgrading them. You can migrate your system components to a new machine that's either running the same version of Windows Server as the source computer or a later version than the source computer.
License conversion converts a particular edition of a specific version of Windows Server to another edition of the same release. All you have to do is run a command and enter the appropriate license key for the edition you want to convert to. For example, if your server is running Windows Server Standard edition, you can convert it to Windows Server Datacenter edition. However, when you convert your edition from Standard to Datacenter, there's no way to reverse the process to return to Standard edition. In some releases of Windows Server, you can also freely convert between original equipment manufacturer (OEM), volume-licensed, and retail versions with the same command and the appropriate license key.
The process of upgrading to a newer version of Windows Server can vary greatly, depending on whichoperating system you are starting with and the pathway you take. We use the following terms todistinguish between different actions, any of which could be involved in a new Windows Serverdeployment.
Upgrade. Also known as an "in-place upgrade". You move from an older version of the operatingsystem to a newer version, while staying on the same physical hardware. This is the method wewill be covering in this section.
In-place upgrades might also be supported by public or private cloud companies; however, youmust check with your cloud provider for the details. Additionally, you'll be unable to performan in-place upgrade on any Windows Server configured to Boot from VHD. An in-place upgradefrom Windows Storage Server Editions is not supported. You can perform either a Migrationor Installation instead.
Cluster OS Rolling Upgrade. You upgrade the operating system of your cluster nodes withoutstopping the Hyper-V or the Scale-Out File Server workloads. This feature allows you to avoiddowntime which could impact Service Level Agreements. For more information, seeCluster OS Rolling Upgrade
License conversion. Convert a particular edition of the release to another edition of the samerelease in a single step with a simple command and the appropriate license key. We call this"license conversion". For example, if your server is running Standard edition, you can convert itto Datacenter.
With Windows Server 2022 and earlier, you can upgrade to a newer version of Windows Server by upto two versions at a time. For example, Windows Server 2016 can be upgraded to Windows Server 2019or Windows Server 2022. If you are using theCluster OS Rolling Upgrade featureyou can only one version at at time.
You can also upgrade from an evaluation version of the operating system to a retail version, from anolder retail version to a newer version, or, in some cases, from a volume-licensed edition of theoperating system to an ordinary retail edition. For more information about upgrade options otherthan in-place upgrade, seeUpgrade and conversion options for Windows Server.
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.
Support for Windows Server 2008 andWindows Server 2008 R2 has ended. We recommend youupdate your version of Windows Server to a more recent version as soon as possible. Learn moreabout Extended Security Updates (ESU) as a last resort.
You would need to either have or purchase 2016 licenses, or have active SA on your 2012R2 licensing. Either way you would need to have access to your installation media and keys. In most cases this is through the Microsoft Volume Licensing Service Center.
You would need to login to VLSC and download your media and keys. Those will enable the ability to run the actual in-place upgrade. If you dont have any licenses available, you will need to purchase more licenses.
2016 changed their licensing model to per-core, with a 16 core minimum. If you are talking about a host running virtual machines, you are required to (at minimum) license every core on the host / cluster.
Going to any version newer than 2016 will require newer CALs as well. If you are using M365, each M365 license includes Windows CALs, so users with M365 license are covered, which makes it a lot less costly to go past 2016.
You need to know how to do per core licensing. If you only upgrade the 2012 VMs and leave the 2016 alone for now, you need a 2022 license for the first host and a 2022 license for the second host. This does not allow you to move VMs between hosts. If you upgrade all 6 Windows VMs, you need to buy two license for the first host and one license for the second host.
Make sure that the server meets the system requirements for Windows Server 2016. Microsoft has a guide that lists the minimum requirements for Windows Server 2016. or please Check application compatibility, Make sure that all the applications running on the server are compatible with Windows Server 2016. Check with the application vendors to ensure that they support Windows Server 2016.
Use the Windows Server Migration Tools: Microsoft provides a set of tools called Windows Server Migration Tools that can help you upgrade from Windows Server 2012 R2 to Windows Server 2016. You can download the tools from the Microsoft website and follow the step-by-step instructions provided to perform the upgrade.
You also mentioned that you have multiple VMs on the physical server. My understanding is that if you upgrade, you will need to install the Datacenter version of Server XXXX as the Standard version can only be licensed for 2 VMs on the physical box
Doing some searches on the web, it's not clear if there is an upgrade path from 2012R2 to 2022 Windows Server. From the link, I was wondering if there is an upgraded diagram, or if Microsoft has a recommendation on the path forward for this route? Is this upgrade not supported, and we should opt to then do a clean install?
@Harm_Veenstra I appreciate the responses. My concern is that is there a official recommendation from Microsoft? Does Microsoft 'standby' that this upgrade path should work, or what I'm reading from other responses is that, it's better to do a clean install, or perform both routes just in case...
Actually migrating to Windows 11 needs much planning and considerations due to heavy changes to the underlying hardware security stack (TPM 2.0, UEFI, Secure Boot, VBS etc.).
Same is true for Windows Server 2022.
Just because it "works" doesn't mean it is properly configured, secured and optimized.
You certainly doesn't want your brand new Windows Server 2022 relying BIOS/MBR model by example.
This is very difficult to do when the DC has hundreds of users and computers and other roles running, especially when you are a new sys admin with no connection to the prior sys admin of anything else the DC vm may be doing that is critical that you can't migrate by doing a fresh install.
@Chrisntpsfor new domain controllers it's better just to spin up a new server 2022 and join it to the domain then make it a domain controller (DNS Server) I've removed all other roles from my domain controllers such as (DHCP, CERT, KMS, other roles) this way it's easier to upgrade domain controllers by adding a new DC already running the latest OS. if you haven't move the roles out of your DC I recommend you to first work on moving DHCP, KMS, Certificate of Authority or any roles you may be running on that DC aside from (DNS only) this role must stay in the DC imho.
@cespiritu @Zach_B635 it depends on the workloads and antivirus apps.
If this is a correctly setup server like "no Domain Controller + Certificate Authority at the same Server or VM it is a simple as