If left blank, the next build will increment the number from the previous build if necessary, and use that. If no previous build used the Version Number Plugin, then this defaults to 1.

If a number is specified here, it will override the number tracked from build to build and the next build will use this number instead. Negative numbers are not allowed and will be ignored.

If an environment-variable is specified here, its value will be retrieved during the next build and will be used as number. However, if that environment-variable is not set or its value is not a (positive) number, the standard behavior will kick in as if this field was left blank. (That means, the number from the previous build will be incremented and used.)

Other values will be ignored as if left blank.