Windows SDK 10.0.26100.4654: Redistribution rights for five x64 UCRT DLLs missing from REDIST.TXT

The current public Microsoft documentation does not explicitly authorize redistribution of those five DLLs, so obtain written confirmation through a Microsoft support incident before shipping them app-local.

What the published terms establish

The Windows SDK license defines “Distributable Code” as object code listed either:

1. In a REDIST.TXT file supplied with the licensed SDK, or
2. On Microsoft’s published REDIST.TXT list.

It also says Microsoft may add files to the list over time.^1^

The public REDIST.TXT page is dated October 21, 2024. Its x64 UCRT section lists many files under Windows Kits\10\Redist\ucrt\DLLs\x64, but the five filenames in the question are not included.^2^

Microsoft separately identifies 10.0.26100.4654 as the July 2025 Windows SDK release, but the available material does not provide a separate public, version-specific REDIST list for that release.^3^

Consequently, presence under the installed Redist directory is relevant technical deployment evidence, but it does not by itself resolve the omission from the licensing list.

Check the SDK package itself

Before escalating, preserve and inspect the licensing artifacts delivered with the exact 10.0.26100.4654 installer or ISO:

1. Search the installed SDK directory and installation media for every file named REDIST.TXT.
2. Search those files for each complete filename—not merely the containing UCRT directory.
3. Record:
   • SDK installer/ISO source and version;
   • installed file paths;
   • DLL versions and SHA-256 hashes;
   • copies of the applicable license and REDIST files;
   • the public REDIST page’s date.

If an SDK-supplied REDIST.TXT explicitly lists the files, that is one of the licensing mechanisms identified by section 2(a)(i). If it does not, the available public documents do not explicitly settle their status.

Why the deployment documentation is not enough

The UCRT deployment documentation says app-local deployment is supported and identifies ucrtbase.dll plus the api-ms-win-*.dll APISet forwarders under the SDK’s Windows Kits\10\Redist\ucrt\DLLs directory. It recommends including all DLLs for local deployment because the required set varies by operating system.^4^

Another UCRT document calls the retail DLLs in that directory “Redistributable files.”^5^

Those pages document supported deployment mechanics. Because the controlling license expressly points to supplied or published REDIST lists, they should not be treated as a substitute for an explicit licensing entry where the filenames are absent. Microsoft’s DLL guidance likewise says only files specified in Redist.txt or the applicable online REDIST list may be redistributed.^6^

Official escalation route

For an authoritative, case-specific response:

1. Use Microsoft Support for Business → Create a support incident.
2. Select the closest available Windows developer/Windows SDK or Developer Tools category.
3. State that the request concerns an apparent mismatch between:
   • Windows SDK 10.0.26100.4654 installation contents;
   • section 2(a)(i) of the SDK license;
   • the public REDIST.TXT page dated October 21, 2024.
4. Request either:
   • the applicable version-specific REDIST artifact,
   • correction of the public list, or
   • written confirmation whether the five named, unmodified x64 binaries are Distributable Code.

Microsoft’s Windows developer support guidance identifies a support incident as the enterprise route and notes that it requires a Microsoft support contract.^7^

Attach the exact filenames, hashes, paths, SDK version, and copies of the supplied licensing files. Until Microsoft provides that clarification—or an SDK-supplied REDIST file explicitly lists them—the conservative release action is to exclude those five app-local files. For Windows 10 and Windows 11 specifically, the system UCRT is used even when an application includes a local copy.^4^

References

1. MICROSOFT SOFTWARE LICENSE TERMS
2. REDIST.TXT
3. Windows SDK downloads
4. Universal CRT deployment
5. Upgrade your code to the Universal CRT
6. Determine which DLLs to redistribute
7. Help and guidance for Windows developers