# Configuration Upgrade/Downgrade

You can perform configuration upgrades or downgrades on the "..." operation page of the instance.

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## Configuration selection

You can re-select the configuration of PostgreSQL(NVMe), including CPU, memory and disk.
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## Price changes

If the configuration is upgraded, the additional cost will be displayed. If it is downgraded, the refunded cost will be displayed.
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## Notes
- During the configuration upgrade/downgrade process, the instance cannot initiate a backup.
- During the upgrade/downgrade process of highly available instances, there will be a master-slave switch, which can cause millisecond-level connection interruptions, and the business can reconnect.
- During the upgrade/downgrade process of single instances, there will be a restart, which can cause second-level connection interruptions, and the business can reconnect.