Database synchonization after 7.1.3 to 8.2.2 upgrade


We are working on 7.1.3 to 8.2.2 upgrade using side by side approach.
As the upgrade steps involve database replication, upgrade and testing activities.
We want to keep 7.1.3 running and catering business while we are making 8.2.2 envionment ready.
Due to there will be possible transaction delta, i.e. transaction ran and went in the webMethods 7.1.3 database after initial DB replication.

We would like to know if it is possible to synchronize this delta from 7.1.3 Database to 8.2.2 database.
As there will be database table update as part of 8.2.2 upgrade process , we are bit unsure on whether DB replication will work.

If andy one has already perform such synchrnization during their upgrade process please share.
Please share if you have used any other cutoff plan for production during upgrade to avoid long downtime and data loss.

Thanks In Advance,
Ashish A Potnis