we will find Assembly version from Assembly.cs in every library.
[assembly: AssemblyVersion(\"1.0.0.0\")]
[assembly: AssemblyFileVersion(\"1.0.0.0\")]
The version number is made up of four segments; Major, Minor, Build and Revision.
The first two segment Major and Minor are the version number that the user will normally see, major changes are for very large change, whilst minor are incremented for each brand new release to the user.
The second two segments Build and Revision are an extension to the version number that are really for IT people. By default these are the number of days since a random, designated start date, and the revision based on the number of seconds since midnight.
We actually use a version of the date for the build value and releases within a single day for the revision (although we will probably move this to being our svn revision number).