Verisure migrated their data warehouse from using Tungsten Replicator to native multi-source replication in MySQL 5.7 to simplify operations. They loaded data from production shards into the new data warehouse setup using XtraBackup backups and improved replication capacity with MySQL's parallel replication features. Some issues were encountered with replication lag reporting and crashes during the upgrade but most were resolved. Monitoring and management tools also required updates to support the new multi-source replication configuration.