Update 6 changed some schema information, which might be where the break is. You could roll back, but because of a lot of existing bugs in RTM, my recommendation would be to update the BizTalk communication. It should not be a major change, and much easier
than trying to roll back the CRM system.
However, if you do need to roll back, you likely will want to uninstall CRM entirely, then install RTM and restore your database, so all the bits match.
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