XDCR replication does not have collections capability

Hi , trying to migrate data from CB 6.6.5 to 7.0.4 by running XDCR replication .
Getting error

“Only default collection from source bucket ‘XXXXXX’ to target bucket ‘XXXXXX’ on cluster ‘XXX.com’ is being replicated because ‘XXX.com’ does not have collections capability”

I understand that in CB 7 there is new future - collections , I just need to copy data from buckets . How it can be done ?