Couchbase Server won't start: Detected an attempt to offline upgrade from unsupported version

Couchbase Server
1

After a AWS node crash our Couchbase Server won’t start. The server logs show this message repeating

[ns_server:error,2021-05-06T21:22:22.832Z,ns_1@kup-couchbase-0.kup-couchbase-headless.couchbase.svc.cluster.local:ns_config<0.193.0>:ns_config_default:upgrade_config:391]Detected an attempt to offline upgrade from unsupported version {6,5,1}. Terminating.

We are running our own couchbase server build in containers, not using a managed Couchbase

2

Hi, I had a similar message in my log.
I upgraded from couchbase-ce v6.6.0 to v7.1.1
The upgrade was done without any trouble. Then I wanted to downgrade back to my old v6.6.0.
That’s how I got this message. Backups and snapshots are always your best friends !