NuGet Warning NU5105

The package version '1.2.3+semver2.metadata' uses SemVer 2.0.0 or components of SemVer 1.0.0 that are not supported on legacy clients. Change the package version to a SemVer 1.0.0 string. If the version contains a release label it must start with a letter. This message can be ignored if the package is not intended for older clients.

Issue

The version property specified contains SemVer 2.0.0 components or SemVer 1.0.0 components that may not be supported on NuGet clients older than v4.3

Solution

If you intend for your package to be available to NuGet clients older than v4.3 then please adapt the version property to be compatible with the legacy clients. You can read more about the SemVer 2.0.0 support here.