Upgraded to DSM7 on Synology, also upgrade to your DSM7 package version, old backup routine gone

Is the info about the old backup set stored anywhere I can get to, or do I have to reconfigure the backup routine from scratch?

The configurations are stored in $SYNOPKG_PKGDEST/.duplicacy-web. That didn’t change in the DSM7 package. However, Synology may have changed the value of $SYNOPKG_PKGDEST, which now seems to /Volume1/@appstore/duplicacy instead of /volume1/homes/admin/. If you can see files in /volume1/homes/admin/.duplicacy-web then you can just copy them to /Volume1/@appstore/duplicacy/.duplicacy-web.