By specifying the version number of the custom component, in the DtsPipelineComponent attribute, you mark the new version of the component; a new version is needed only if the exposed properties, inputs, and/or outputs, have been modified.
Of course, setting the new version number is not enough to allow the earlier versions of the component that are already in use in deployed SSIS packages to be upgraded accordingly. The upgrade is performed by overriding the PerformUpgrade() base class method. In the preceding example, a new component custom property is added.
After the upgrade, the component's version number is changed as well, to the version number of the component currently registered in the GAC.
When the new version of ...