Unable to create chart with json and dot in key

I have tried to create a donut chart for Chrome version. Which contain a dot as key. This will cause errors. I have tried to create the chart on http://c3js.org (c3.min-4c5bef8f.js) with a chrome (50.0). But it was not possible.

var chart = c3.generate({
    data: {
        json: [
            {'38.0': 10, '46.0': 10, '47.0': 10, '49.0': 20, '50.0': 30, 'unbekannt': 4}
        ],
        keys: {
            value: ['38.0', '46.0', '47.0', '49.0', '50.0', 'unbekannt']
        },
        type : 'donut'
    },
    donut: {
        title: "Chrome Versions"
    }
});

[scherrs]

It seems that this issue is still open in the current version, isn’t it?

We have a problem similar to the described behavior.

[miladtai]

I have this problem too, how we can solve this ?