Joe,
the only problem i know with 5.1.5 is the issue with content_type__create_attribute(see https://openacs.org/forums/message-view?message_id=349019)
which is in turn only needed so far for the page templates/page instances (see http://media.wu-wien.ac.at/download/xowiki-doc/index.html towards the end). it should not be a big problem to make it conditionally, such one can use the rest of the package. Would this help you?
