If a customer is unable to upgrade Deep Security Manager (DSM) from version 20.0.651 to 20.0.879, and receives an error message indicating a software version and schema version mismatch, it is likely that another node upgrade failed and rolled back, but the database is already in version 20.0.879, preventing the service from starting.
As a workaround, customers may install or add a new node. Please refer to the documentation for instructions on how to add a node if manager versions are mismatched.
For more information, please refer to the following references: