Upgrading Issues

I’m preparing for a re-launch of a site using CouponPress so I unpacked the old site based on v6.x I think, imported the old database to a development server then upgraded to v8.x and all of the coupons from v6.x of the site quite displaying.

Has something changed that I should know about or is there a new upgrade process? v8.x also seems to have broken our custom import tool written for v6.x sites. New column headers in the database?

Some input and/or direction would be appreciated.

Thank you.