From:
https://www.microsoft.com/en-us/UseTerms/Retail/WindowsServer2019/DatacenterAndStandard/Useterms_Retail_WindowsServer2019_DatacenterAndStandard_English.htm
^^ NOTICE its states "RETAIL" in the link.
This link contains also the EXACT same text that is installed on Windows Server 2019 Std edition in the C:\Windows\System32\License.RTF file AFTER you activate and apply a purchased RETAIL license KEY.
So where does everyone get the miss-information that you Can't apply Downgrade rights to Retail licenses??
Last updated April 2018
MICROSOFT SOFTWARE LICENSE TERMS
MICROSOFT WINDOWS SERVER
- License Model Overview.
- Definitions
- How to License Server Software
- Windows Server Client Access Licenses (CALs)
- Additional Licensing Provisions
5b. Downgrade Rights.
Instead of creating, storing, and using the software, for each permitted instance, you may create, store, and use an earlier version of the following editions of the software for so long as Microsoft provides support for that earlier version as set forth in (aka.ms/windowslifecycle):
**For Windows Server Standard**
· Windows Server Standard
· Windows Server Essentials
· Windows Server Foundation
· Windows Server Enterprise
· Windows Web Server
· Windows HPC Server Operating System
**For Windows Server Datacenter**
· Windows Server Datacenter
· Windows Server Standard
· Windows Server Essentials
· Windows Server Foundation
· Windows Server Enterprise
· Windows Web Server
· Windows HPC Server Operating System
This agreement applies to your use of the earlier versions of the editions listed above. For the avoidance of doubt, by electing this downgrade option: (i) you will not have the right to create, store, or use a greater number of instances of the software than are permitted under this agreement, and (ii) you will need to acquire licenses for all cores in the physical server in accordance with Section 3 of this agreement. If the earlier version includes different components not covered in this agreement, the terms that are associated with those components in the earlier version of these editions apply to your use of them. Neither the manufacturer or installer, nor Microsoft is obligated to supply earlier versions or other editions to you. At any time, you may replace an earlier version or edition with this version and edition of the software.