How to use a custom element inside react?

Custom elements can be of two kinds:
<!-- variant 1 -->
<my-tag></my-tag>
<!-- variant 2 -->
<div is="my-tag"></div>

So, why in react16 the second option is not working?
<!-- works 15, works 16 -->
<div is="chart-01" data-stars="0;1;2;3;4;5"></div>
<!-- works in 15 and 16 -->
<chart-data 02-stars="5;4;3;2;1"></chart-02>

Example реакт15 (codepen)

Example реакт16 (codepen)
June 8th 19 at 16:33

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