System.Version Class

Represents the version number of an assembly, operating system, or the common language runtime. This class cannot be inherited.

See Also: Version Members


public sealed class Version : ICloneable, IComparable, IComparable<Version>, IEquatable<Version>


Version numbers consist of two to four components: major, minor, build, and revision. The major and minor components are required; the build and revision components are optional, but the build component is required if the revision component is defined. All defined components must be integers greater than or equal to 0. 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:

Subsequent versions of an assembly that differ only by build or revision numbers are considered to be Hotfix updates of the prior version.

Starting with .NET Framework 2.0, the Version.MajorRevision and Version.MinorRevision properties enable you to identify a temporary version of your application that, for example, corrects a problem until you can release a permanent solution. Furthermore, the Windows NT operating system uses the Version.MajorRevision property to encode the service pack number.

Assigning Version Information to Assemblies

Ordinarily, the Version class is not used to assign a version number to an assembly. Instead, the System.Reflection.AssemblyVersionAttribute class is used to define an assembly's version, as illustrated by the example in this topic.

Retrieving Version Information

Version objects are most frequently used to store version information about some system or application component (such as the operating system), the common language runtime, the current application's executable, or a particular assembly. The following examples illustrate some of the most common scenarios:

Comparing Version Objects

You can use the Version.CompareTo(Version) method to determine whether one Version object is earlier than, the same as, or later than a second Version object. The following example indicates that Version 2.1 is later than Version 2.0.

code reference: System.Version.Class.Comparing#1

For two versions to be equal, the major, minor, build, and revision numbers of the first Version object must be identical to those of the second Version object. If the build or revision number of a Version object is undefined, that Version object is considered to be earlier than a Version object whose build or revision number is equal to zero. The following example illustrates this by comparing three Version objects that have undefined version components.

code reference: System.Version.Class.Comparing#2

Thread Safety

All public static members of this type are safe for multithreaded operations. No instance members are guaranteed to be thread safe.


Namespace: System
Assembly: mscorlib (in mscorlib.dll)
Assembly Versions: 1.0.5000.0,,