nuget 'NU1605: Detected package downgrade' - how to fix

TL;DR

A direct package reference pins a lower version than some other package in the graph requires. Raise the direct reference to at least the required version (or remove it and let the transitive version win), then restore. The higher version is almost always the right one.

Error

nuget 'NU1605: Detected package downgrade'  -  how to fix

Steps

1. Read the NU1605 message: it names the package, the version you asked for, and the higher version something else needs. Expected output: You know both versions and which project holds the low pin.

2. Find the low pin: check the project file and any Directory.Packages.props for the direct reference. Expected output: You locate the exact line pinning the lower version.

3. Raise it: set the reference to the higher version (or remove the direct reference if the transitive one suffices). Expected output: No reference asks for less than the graph needs.

4. Restore: dotnet restore. Expected output: NU1605 is gone and restore completes.

5. Build and test: dotnet build, then the test suite. Expected output: Everything passes on the unified version.

When to use

• Restore fails with NU1605 detected package downgrade
• A direct reference pins an older version than a transitive dependency requires
• Central package management has a stray low pin in Directory.Packages.props

When not to use

• The error is NU1101; the package version does not exist on the feed
• The error is NU1202; the issue is framework targeting, not version ordering
• You genuinely need the older version; then the newer dependent must be downgraded instead, carefully

Variant phrasings

NU1605 after adding a new package reference

The new reference's transitive graph needs more than an existing direct pin.

Detected package downgrade in central package management

The pin lives in Directory.Packages.props; fix it there once for all projects.

Transitive dependency outranks a direct pin

Remove the direct pin and let the graph's higher version flow through.

Why it happens

NuGet resolves each package to a single version per project, and it refuses to silently downgrade: if your direct reference says 1.0 but another package needs 2.0, picking 1.0 would break that package. NU1605 forces you to choose explicitly, and the higher version is the safe default since the dependent was built against it.

Edge cases

• Removing the direct pin entirely is cleanest when nothing in your code uses the package directly.
• Downgrading the dependent to match your pin is occasionally right, but verify its own dependencies still resolve.
• Multi-targeted projects can NU1605 on one framework only; check the per-framework assets.

Provenance

Resolved from the public thread: https://vectle.com/posts/pstlBHS-OucPoRiO7C3E3_AQ

Resolved from the public thread: https://vectle.com/posts/pstlBHS-OucPoRiO7C3E3_AQ

Thread query: nuget 'NU1605: Detected package downgrade' - how to fix

TL;DR: A direct package reference pins a lower version than some other package in the graph requires. Raise the direct reference to at least the required version (or remove it and let the transitive version win), then restore. The higher version is almost always the right one.