When creating a patch, you must specify a version number in the format major.minor.build.revision. For a patch, you can only set the final two parts: the build and revision numbers. The build number is automatically incremented.
The version for a patch must have the same major and minor number, and a higher build or release number than the parent solution version number.
If a solution has multiple patches, new patches must have a higher build or release number than any of the other existing patches for that solution.