GDPR: gathering retro-active consent

It looks like SuiteCRM 7.10.x will not be stable enough for us to upgrade our system until end of April by which time we need to be sending out email campaigns to ask our current leads and contacts for consent in order to be able to correspond with them after 25.5.2018 (when GDPR goes into effect).

How are you all going about this with Pre-7.10.x versions?
We’re thinking of moving to Mailchimp for mass-email campaigns. (to have more control over customer consent, as we have multiple independent services for which we need customer consent, not just once per email address). But that would mean extra cost and we’ve been successfully using Sugar/SuiteCRM for years now. Just not sure at this point how to pull it off in a GDPR-compliant way before SuiteCRM 7.10.x.

I’m thinking we’d have to add custom fields, build custom scripts, logichooks with customized email campaign etc. to do this automatically. Not sure I’ll be able to figure that out.
We could do something manual like setting up a single consent-gathering campaign in Mailchimp and then manually transferring the consent status to hundreds or thousands of leads and contacts… This would be barely feasible but even so not very elegant, because the direct proof of consent would be logged in Mailchimp, not in our CRM.

What would be a quick-and-dirty way to pull this retroactive-consent-gathering off? Appreciate any ideas!

Just learned about the feature “Sending/Resending Opt In Emails Manually”. Great to know v7.10.x has this built in!