A version number is composed of the following four fields: major.minor.revision.build. By itself a version number is not all that meaningful. The version number is only valuable to denote change. Here is a way to make sense of version numbers and to use them effectively.
Technical Reasons for Using Version Numbers
The major version number of a component is incremented if the program interface of the component is changed and other components using this component will stop operating as a result of the program interface change.
The minor version number of a component is incremented if new program interface elements are added to the software component. The incrementing of the minor version number allows other components to take advantage of the added functionality that the current component provides.
The revision number of a component is incremented if a component implements a fix to a known software defect. This allows user components to implement fixes for the known defect or a user program can refuse to run with the defective component. The calling application can advise the user to get an upgraded component.
The build number of a component is always incremented when the project owner decides to create a new release during the implementation of the project. This helps us in uniquely identifying every released build, which aids us in in tracking down defects.
Marketing Reasons for Using Version Numbers
The major version number is incremented every time a significant enhancement is made to the software product.
The minor version number is incremented if a smaller scale improvement is made to the software product. These two version numbers are usually used prominently on marketing packages and literature.
The revision number is used only for software defect fixes. The revision number is incremented every time a defect fix has to be implemented in the software product.
The build number is used for internal purposes only. This number is incremented every time a project owner decides to release a new version of his/her project.
Every time a component of the version number is incremented, all components that are to the right of that component will be reset to zero. Example: The current version for a product is 3.5.2.234. We have just made a defect fix and have to increment the revision number, then the new version number is: 3.5.3.0.
Frequently Asked Questions about Version Numbers
Q: Do I have to update the version number of my product before each build?
A: No. You only have to update the version number of your project when you are ready to make a new release of your project. You will have to update the major, minor, revision, & build numbers for your products and packages.
Q: How do I know that the correct version number was set on my product?
A: You can check the version number of your product in Windows Explorer. Select your product .exe or .dll file and then choose "Properties" from the right-click menu. Select the version tab. You should see the version information displayed here.