You are upgrading Istio and a message like this pops up:
WARNING: Istio is being downgraded from 1.20.0 to 1.19.3. Before upgrading, you may wish to use 'istioctl x precheck' to check for upgrade warnings.
Not very obvious what happens the first time one comes across this.
The reason is simple:
- The control plane is at version 1.20.0.
- The istioctl binary is at version 1.19.3.
The fix: update istioctl to the matching 1.20.0 version to remove this warning.