A number that identifies the set of components uploaded in a package. The version number has the format majorNumber. minorNumber. patchNumber (for example, 2. 1. 3). The major and minor numbers increase to a chosen value during every major release. The patchNumber is generated and updated only for a patch release. If there is no patchNumber, it is assumed to be zero (0). Patch versions are currently available through a pilot program. For information on enabling patch versions for your organization, contact salesforce.com.

Unmanaged packages are not upgradeable, so each package version is simply a set of components for distribution. A package version has more significance for managed packages. Packages can exhibit different behavior for different versions.

Publishers can use package versions to evolve the components in their managed packages gracefully by releasing subsequent package versions without breaking existing customer integrations using the package. See also Patch and Patch Development Organization.