Once https://github.com/elastic/elasticsearch/issues/98503 is done, we can use our minimum version numbers in the SystemIndexMappingUpdate service instead of the old `Version` types. Mappings will be updated for a system index when all nodes have a matching descriptor mappings version for a system index, but this version is greater than what's stored in the mappings metadata.
server/src/main/java/org/elasticsearch/cluster/ClusterState.java
customs.build(),
                fromDiff,
                routingNodes
            );
        }
        public static byte[] toBytes(ClusterState state) throws IOException {
            BytesStreamOutput os = new BytesStreamOutput();
            state.writeTo(os);
            return BytesReference.toBytes(os.bytes());
        }
        /**
         * @param data      input bytes
         * @param localNode used to set the local node in the cluster state.
         */
        public static ClusterState fromBytes(byte[] data, DiscoveryNode localNode, NamedWriteableRegistry registry) throws IOException {
            StreamInput in = new NamedWriteableAwareStreamInput(StreamInput.wrap(data), registry);
            return readFrom(in, localNode);
        }
    }
    @Override
    public Diff<ClusterState> diff(ClusterState previousState) {
        return new ClusterStateDiff(previousState, this);
    }
    public static Diff<ClusterState> readDiffFrom(StreamInput in, DiscoveryNode localNode) throws IOException {
        return new ClusterStateDiff(in, localNode);
    }
    public static ClusterState readFrom(StreamInput in, DiscoveryNode localNode) throws IOException {
        ClusterName clusterName = new ClusterName(in);
        Builder builder = new Builder(clusterName);
        builder.version = in.readLong();