Overview of how .NET is versioned

The .NET Runtime and the .NET SDK add new features at different frequencies. In general, the SDK is updated more frequently than the Runtime. This article explains the runtime and the SDK version numbers.

Versioning details

The .NET Runtime has a major/minor/patch approach to versioning that follows semantic versioning.

The .NET SDK doesn't follow semantic versioning. The .NET SDK releases faster and its version numbers must communicate both the aligned runtime and the SDK's own minor and patch releases.

The first two positions of the .NET SDK version number are locked to the .NET Runtime version it released with. Each version of the SDK can create applications for this runtime or any lower version.

The third position of the SDK version number communicates both the minor and patch number. The minor version is multiplied by 100. The final two digits represent the patch number. Minor version 1, patch version 2 would be represented as 102. For example, here's a possible sequence of runtime and SDK version numbers:

Change .NET Runtime .NET SDK (*)
Initial release 2.2.0 2.2.100
SDK patch 2.2.0 2.2.101
Runtime and SDK patch 2.2.1 2.2.102
SDK feature change 2.2.1 2.2.200

NOTES:

  • If the SDK has 10 feature updates before a runtime feature update, version numbers roll into the 1000 series with numbers like 2.2.1000 as the feature release following 2.2.900. This situation isn't expected to occur.
  • 99 patch releases without a feature release won't occur. If a release approaches this number, it forces a feature release.

You can see more details in the initial proposal at the dotnet/designs repository.

Semantic versioning

The .NET Runtime roughly adheres to Semantic Versioning (SemVer), adopting the use of MAJOR.MINOR.PATCH versioning, using the various parts of the version number to describe the degree and type of change.

MAJOR.MINOR.PATCH[-PRERELEASE-BUILDNUMBER]

The optional PRERELEASE and BUILDNUMBER parts are never part of supported releases and only exist on nightly builds, local builds from source targets, and unsupported preview releases.

Understand runtime version number changes

MAJOR is incremented when:

  • Significant changes occur to the product, or a new product direction.
  • Breaking changes were taken. There's a high bar to accepting breaking changes.
  • An old version is no longer supported.
  • A newer MAJOR version of an existing dependency is adopted.

MINOR is incremented when:

  • Public API surface area is added.
  • A new behavior is added.
  • A newer MINOR version of an existing dependency is adopted.
  • A new dependency is introduced.

PATCH is incremented when:

  • Bug fixes are made.
  • Support for a newer platform is added.
  • A newer PATCH version of an existing dependency is adopted.
  • Any other change doesn't fit one of the previous cases.

When there are multiple changes, the highest element affected by individual changes is incremented, and the following ones are reset to zero. For example, when MAJOR is incremented, MINOR and PATCH are reset to zero. When MINOR is incremented, PATCH is reset to zero while MAJOR is left untouched.

Version numbers in file names

The files downloaded for .NET carry the version, for example, dotnet-sdk-2.1.300-win10-x64.exe.

Preview versions

Preview versions have a -preview[number]-([build]|"final") appended to the version number. For example, 2.0.0-preview1-final.

Servicing versions

After a release goes out, the release branches generally stop producing daily builds and instead start producing servicing builds. Servicing versions have a -servicing-[number] appended to the version. For example, 2.0.1-servicing-006924.

Relationship to .NET Standard versions

.NET Standard consists of a .NET reference assembly. There are multiple implementations specific to each platform. The reference assembly contains the definition of .NET APIs which are part of a given .NET Standard version. Each implementation fulfills the .NET Standard contract on the specific platform.

The .NET Standard reference assembly uses a MAJOR.MINOR versioning scheme. PATCH level isn't useful for .NET Standard because it exposes only an API specification (no implementation) and by definition any change to the API would represent a change in the feature set, and thus a new MINOR version.

The implementations on each platform may be updated, typically as part of the platform release, and thus not evident to the programmers using .NET Standard on that platform.

For more information, see .NET Standard.

See also