upgrade Directory Reference

Directory dependency graph for upgrade:

Directories
directory	model

Files
file	ItemDataUpgrader.php [code]
file	ItemIdMetaUpgrader.php [code]
file	ItemIdMetaUpgradeSchema.php [code]
file	ItemIdMetaUpgradeSchemaUtils.php [code]
file	LegacyItemIdToStringIdMap.php [code]
file	R12ItemIdToBlockIdMap.php [code]