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R18-05121 and R18-05767 are both Windows Server Device CALs; the difference is the server version their access rights cover. R18-05121 is the 2016-generation CAL, while R18-05767 is the 2019-generation CAL. For Windows Server 2019, use a 2019-or-newer CAL—not a 2016 CAL. A 2019 CAL can generally cover access to Windows Server 2016 under qualifying Microsoft Commercial Licensing terms, but confirm the rights in your agreement and Product Terms.
At a glance
| Item | R18-05121 | R18-05767 |
|---|---|---|
| Catalog description | WinSvrCAL 2016 SNGL OLP NL DvcCAL | WinSvrCAL 2019 SNGL OLP NL DvcCAL |
| License type | Windows Server Device CAL | Windows Server Device CAL |
| Version | 2016 | 2019 |
| Windows Server 2016 access | Generally appropriate, subject to entitlement | Generally permitted under qualifying downgrade rights |
| Windows Server 2019 access | Do not assume it is permitted | Generally appropriate, subject to entitlement |
| Windows Server operating system included? | No | No |
| Remote Desktop Services CAL included? | No | No |
| Software Assurance included? | Not indicated by this SKU | Not indicated by this SKU |
| License channel in SKU name | Legacy Open License (OLP) | Legacy Open License (OLP) |
This is a practical summary, not a substitute for the Microsoft Product Terms or the specific agreement under which a license was acquired. Microsoft says Commercial Licensing server licenses include downgrade rights to earlier versions; the agreement and Product Terms remain controlling. See Microsoft’s downgrade-rights guidance.
What the SKU names mean
- WinSvrCAL: Windows Server Client Access License. A CAL is an access right, not a copy of Windows Server.
- 2016 or 2019: The CAL generation. As a general rule, the CAL version must be at least as new as the Windows Server version being accessed.
- SNGL: A single-language designation in catalog naming. It does not mean the license covers only one device; the Device CAL designation is what matters for counting.
- OLP: Open License Program, a legacy Microsoft commercial licensing channel.
- NL: No Level, a volume-pricing designation—not a server edition, support tier, or technical feature.
- DvcCAL: Device CAL. The license is associated with a device rather than an individual user.
Catalog records identify R18-05121 as a Windows Server 2016 Device CAL and R18-05767 as a Windows Server 2019 Device CAL. These are reseller references, not a replacement for proof of Microsoft entitlement.
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Which version can access which server?
The key distinction is the direction of version rights. A newer CAL may generally be used for an earlier server version where the governing licensing terms allow it. An older CAL does not normally grant access rights to a newer server version. Downgrade rights run downward; they do not turn a 2016 CAL into a 2019 CAL.
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| Device CAL generation | Windows Server 2016 | Windows Server 2019 |
|---|---|---|
| 2016 CAL | Generally yes, with valid entitlement | No—do not treat it as sufficient |
| 2019 CAL | Generally yes under applicable downgrade rights | Generally yes |
| Newer CAL | Generally yes for older versions, subject to terms | Generally yes |
Microsoft’s Commercial Licensing guidance describes rights to use earlier versions of licensed server software. That guidance concerns licensing rights, not whether a connection technically succeeds. A server accepting a connection does not establish that the device is properly licensed.
For a mixed 2016/2019 estate, a valid 2019-generation CAL is usually the simpler version choice because it can generally cover both generations under qualifying terms. Keep entitlement records and document the licensing basis. Do not assume the same result for every OEM, retail, academic, government, nonprofit, hosting, or service-provider arrangement.
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- Server 2022 Standard 16 Core
Device CAL or User CAL?
A Device CAL is assigned to a device that accesses covered Windows Server services. Multiple people can use that licensed device, subject to the applicable terms. A User CAL instead follows one person, who can access the server from multiple devices.
- Shared terminals or kiosks: If several shifts or employees use a smaller number of workstations, Device CALs may fit the usage pattern.
- Many devices per employee: If each person uses a desktop, laptop, and tablet, compare the number of devices with the number of users; User CALs may be more efficient.
- Remote or mobile work: Count the devices accessing the server under a Device CAL model. Do not count only employee headcount.
For example, 20 employees sharing 10 terminals may point toward 10 Device CALs, while 10 employees each using three devices could mean 30 devices to license. These examples illustrate the counting distinction; they do not resolve special access, reassignment, or indirect-access rules. Check the agreement and Microsoft licensing information for your scenario.
What these CALs do not include
- Windows Server itself: You still need the appropriate server operating-system license. Server licensing and CALs are separate. Microsoft’s Windows Server 2016 licensing datasheet describes the server-license-plus-CAL model.
- Remote Desktop Services rights: A standard Windows Server CAL is not an RDS CAL. Remote Desktop Services use may require a separate RDS User CAL or Device CAL. Check the applicable requirements for the deployment.
- Automatic upgrades: A 2019 CAL does not automatically provide rights to every later Windows Server version. Downgrade rights and upgrade rights are different.
- Software Assurance: Neither SKU name indicates Software Assurance. Verify the order, agreement, and entitlement record rather than assuming it is included.
- Hosting or external-user rights: Customer-facing hosted services and access by external users may require a different licensing model. A standard internal Device CAL assumption may not fit.
- Extra virtual-machine rights: CALs address access; they do not grant additional Windows Server VM rights. Virtualization affects server licensing, while access rights must also be assessed.
Microsoft’s fulfillment guidance explains that Volume Licensing customers may use prior versions of licensed software and may need to obtain older media or keys separately. Media, keys, and license entitlement are distinct matters.
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These part numbers carry legacy Open License naming. Microsoft’s old Open License ordering route is not the normal route for new commercial license purchases. A reseller catalog reports that R18-05767 was withdrawn and associates the Open License program’s closure for new business with 2019; treat that as a reseller-catalog report, not a current Microsoft confirmation. An indexed listing or leftover inventory is not proof that a transaction is valid, properly licensed, or transferable.
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- CLIENT ACCESS LICENSES (CALs) are required for every User or Device accessing Windows Server Standard or Windows Server Datacenter
- WINDOWS SERVER 2022 CALs PROVIDE ACCESS to Windows Server 2019 or any previous version.
- A USER CLIENT ACCESS LICENSE (CAL) gives users with multiple devices the right to access services on Windows Server Standard and Datacenter editions.
- GENUINE WINDOWS SERVER SOFTWARE IS BRANDED BY MICROSOFT ONLY.
If you already own R18-05121 and use only Windows Server 2016 or earlier, retain the purchase and entitlement records and verify the terms before replacing it. If you need access to Windows Server 2019, do not rely on a 2016 CAL. For a new purchase, ask a Microsoft licensing partner to identify the current applicable channel, SKU, eligibility, and written version rights. Microsoft provides licensing and partner information at microsoft.com/licensing and through its partner directory.
Before buying legacy stock, require documentation that identifies the program and license entitlement, the license’s acquisition and transfer history where relevant, and the version rights. A product key, download, marketplace listing, or emailed certificate alone does not establish a valid license. Academic, government, nonprofit, and commercial SKUs are not automatically interchangeable; use only a program for which the organization qualifies.
Common deployment scenarios
- Windows Server 2016 only: Valid 2016 Device CALs may remain suitable. A 2019 CAL can generally cover the earlier server under qualifying downgrade rights, but there is no reason to replace a valid entitlement solely because a newer CAL exists.
- Windows Server 2019: Use a 2019-or-newer CAL for each applicable device. Do not infer licensing compliance from successful logons.
- Mixed 2016 and 2019 servers: Standardizing on 2019-or-newer CALs can simplify version management, subject to the agreement and legitimate entitlement.
- Hyper-V or other virtualized servers: CAL requirements generally relate to devices or users accessing Windows Server services, not simply the number of VMs. The server software’s core and virtualization licensing is a separate calculation.
- Remote desktops or published applications: Review both standard Windows Server CALs and the separate RDS CAL requirement.
- Customers, partners, or hosted services: Get licensing advice for external access and service-provider terms before using these internal-use assumptions.
Pre-purchase check
- Confirm the Windows Server version and the server licensing position.
- Count the devices that access covered services; compare User CALs if each person uses multiple devices.
- Identify RDS, external-user, indirect-access, hosting, and service-provider scenarios.
- Confirm the exact commercial, academic, government, or other eligibility and the agreement governing the license.
- Verify whether Software Assurance is present and what it actually provides.
- Obtain entitlement records and written confirmation of version rights from a qualified Microsoft licensing partner; do not rely on a key or listing alone.
Windows Server 2016 and 2019 are legacy generations. Check their current lifecycle entries directly in Microsoft’s product lifecycle search rather than treating a CAL purchase as a support or security-update guarantee.
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