To migrate CBPolicyD database from old server to new server, I usually use two methods. The first method is rsync from the old server to the new server. The second method is to export/dump the database on the old server. Then import it on a new server.
1. Move/Migrate database using Rsync
Please stop all Zimbra services (especially cbpolicyd service) to ensure there is no locked database. Run this command from the old server
rsync -avP /opt/zimbra/data/cbpolicyd/db/cbpolicyd.sqlitedb root@newserver:/opt/zimbra/data/cbpolicyd/db/cbpolicyd.sqlitedb
Now, you can restart the Zimbra service on the new server. Then check the cbpolicyd.sqlitedb from Web Admin or the sqlite3 command
2. Export/Import database
# On the old server
export database
cd /opt/zimbra/data/cbpolicyd/db/ sqlite3 cbpolicyd.sqlitedb ".dump $i" >> /tmp/dmp-cbpolicyd.sql

rsync the export result to the new server
rsync -avP /tmp/dmp-cbpolicyd.sql root@newserver:/tmp/
# On the new server
cd /opt/zimbra/data/cbpolicyd/db/ sqlite3 cbpolicyd.sqlitedb < /tmp/dmp-cbpolicyd.sql
You can check the import result by access cbpolicyd.sqlitedb database from WebUI or sqlite3 command
Good luck 🙂