PackageVersionHeader

Specifies the package version for each installed managed package. A package version is 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. As well as a set of components, a package version encompasses specific behavior. 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.

A managed package can have several versions with different content and behavior. This header allows you to specify the version used for each package referenced by your API client. If a package version is not specified for a package, the API client uses the version of the package that is selected in the Version Settings section under Setup, in Develop | API. This header is available in API version 16.0 and later.