I was using the activeClassName property to add a new class to the link when it is in active state.it worked well in version 5.0.3 of react-router-dom . but in version 6.0.2 it started showing me warning and its not working. I couldn't able to find any descriptions about this change in the documents given in react-router website .
<NavLink
className={classes.registerButton}
activeClassName={classes.active}
to="/auth/SignUp"
>cart</NavLink>
image of the warning which was shown in the developer console