The database migration has been completed and data integrity checks have passed.
At 4:45AM CST we restored access to an internal test instance of the application and verified that systems we working as intended.
At 4:50AM CST we reconfigured all applications to talk to the new database cluster and removed access credentials for the old cluster. At that time, all applications were taken out of Maintenance Mode and became available for use.
As expected, hundreds of point of sale systems reconnected within minutes.