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Version Class

Represents the version number for a common language runtime assembly. This class cannot be inherited.

For a list of all members of this type, see Version Members.


[Visual Basic]
NotInheritable Public Class Version
   Implements ICloneable, IComparable
public sealed class Version : ICloneable, IComparable
public __gc __sealed class Version : public ICloneable,
class Version implements ICloneable, IComparable

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.


Version numbers consist of two to four components: major, minor, build, and revision. Components major and minor are required. Components build and revision are optional, but the revision component is only optional if the build component is not defined. All defined components must be decimal integers greater than or equal to 0. Metadata restricts the major, minor, build, and revision components to a maximum value of MaxValue- 1.

The format of the version number is as follows. Optional components are shown in square brackets ('[' and ']'):


The components are used by convention as follows:

  • Major: Assemblies with the same name but different major versions are not interchangeable. This would be appropriate, for example, for a major rewrite of a product where backward compatibility cannot be assumed.
  • Minor: If the name and major number on two assemblies are the same, but the minor number is different, this indicates significant enhancement with the intention of backward compatibility. This would be appropriate, for example, on a point release of a product or a fully backward compatible new version of a product.
  • Build: A difference in build number represents a recompilation of the same source. This would be appropriate because of processor, platform, or compiler changes.
  • Revision: Assemblies with the same name, major, and minor version numbers but different revisions are intended to be fully interchangeable. This would be appropriate to fix a security hole in a previously released assembly.

Subsequent versions of an assembly that differ only by build or revision numbers are considered to be Quick Fix Engineering (QFE) updates of the prior version. If necessary, the build and revision numbers can be honored by changing the version policy in the configuration.

This class implements the ICloneable and IComparable interfaces.


Namespace: System

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, .NET Compact Framework

Assembly: Mscorlib (in Mscorlib.dll)

See Also

Version Members | System Namespace