Please update to v3.3.0RC 15 which contains the London hard fork transition.
Most node operators use the --chain=xdai flag when running a node. In this case, you will only need to update the client. If you use a local spec.json file, you will need to upgrade to this version before restarting your node with the updated OE version.
Set docker image in docker-compose.yml to
Restart your node
docker-compose up -d
There may be an additional instruction related to a variable update following the HF.
Upgrade to version v1.11.7. This is the latest Nethermind release.
Set docker image as image: nethermind/nethermind:latest