private String buildNodesNotYetConvergedMessage(long taskConvergeVersion) {
        var nodes = enumerateNodesNotYetAckedAtLeastVersion(taskConvergeVersion);
        if (nodes.isEmpty()) {
            return "";
        }
        return String.format("the following nodes have not converged to at least version %d: %s",
                taskConvergeVersion, stringifyListWithLimits(nodes, options.maxDivergentNodesPrintedInTaskErrorMessages()));
    }
This is called when the options field has been set to a new set of options
clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/FleetController.java