What is the correct way to use custom element inside react?

Question

React

Custom elements are of two types:

<!-- variant 1 -->
<my-tag></my-tag>
<!-- variant 2 -->
<div is="my-tag"></div>

So, why does the second option not work in react16?

<!-- работает в 15, не работает в 16 -->
<div is="chart-01" data-stars="0;1;2;3;4;5"></div>
<!-- работает и в 15 и в 16 -->
<chart-02 data-stars="5;4;3;2;1"></chart-02>

React15 example (codepen) React16
example (codepen)