com.liferay.portal.kernel.upgrade
Classes 
BaseUpgradeAdminPortlets
BaseUpgradePortletPreferences
CamelCaseUpgradePortletPreferences
MockPortletPreferences
RenameUpgradePortalPreferences
RenameUpgradePortletPreferences
UpgradeProcess
Exceptions 
OlderVersionException
StagnantRowException
UpgradeException