SSE-C allows an S3 client to en/decrypt an object at the MinIO server. Therefore the S3 client sends a secret key as part of the HTTP request. This secret key is **never** stored by the MinIO server and only resides in RAM during the en/decryption process.

To perform bi-directional replication, repeat the above process on the target site - this time setting the source bucket as the replication target. It is recommended that replication be run in a system with at least two CPU's available to the process, so that replication can run in its own thread.

- For installations using Systemd MinIO service, upgrade via RPM/DEB packages **parallelly** on all servers or replace the binary lets say `/opt/bin/minio` on all nodes, apply executable permissions `chmod +x /opt/bin/minio` and process to perform `mc admin service restart alias/`.

### Upgrade Checklist