dotnet 10 SDK folders

[esimers]

Can someone please explain to me which ones of these .dll files I'm supposed to be using.
There are some in main x64 folder then there is also some with the SAME names in the "\bin\core\" folder....  

Now I assume that when everything was moving away from "framework" to "core" dotnet is where this all came from.  But now we are dotnet 10 required? At least that's how its worded in the documentations I've seen.  Which "version" of these files are they?  furthermore if the ones in the main folder are framework related...why is it even in there when it doesn't even work?  As a very novice beginner dev it gets confusing.

[esimers]

Bueller...  

[Markus.Koechl · Accepted solution]

Vault started delivering .NET Core targeting SDK dlls with Vault 2025. The Vault Client 2025 continued to be a .NET Framework-based application. Therefore, the SDK continued to deliver .NET FW dlls in the SDK folder ./x64. At the same time, Inventor, AutoCAD, and Revit moved to .NET Core, and the Vault Add-Ins for these had to follow this path. The SDK added the x64/Core dlls to support these add-ins and custom CAD addins interfacing with Vault.
Vault 2026 Client is also rebased on .NET Core. So, Inventor, AutoCAD, Revit, Vault Client customizations consume SDK libraries from the .\Core subfolder only. But other Autodesk applications (e.g., Navisworks), and likely custom standalone applications connecting to Vault, continue to be based on .NET Framework. That's why the Vault SDK will continue sharing libraries targeting both platforms.
Now, looking in detail at the .NET Core versions, it's not getting any easier, and I hope my table helps to identify the .NET version you need. Upgrading legacy releases to the latest .NET Core is enforced by Microsoft's new lifecycle policy, which supports a version for 2 years.

	.NET 8	.NET 10
2027..		X
2026..2026.3	X
2026.4 onwards		X
2025..2025.4	X
2025.5 onwards		X