Vault Upgrade Hook

The tool is about upgrading user generated or other non-static content during content package installation via the Jackrabbit file vault. It implements a common framework to run upgrade mechanisms which we see in all our client projects via an InstallHook. We plan to release the first version of the tool within the next weeks and I'd like to present the functionality at the adaptTo() because the use cases covered by the vault-upgrade-hook are very common and relevant.