AirPods not updating

Please check your model of AirPods and versions compatibility.

Also take a look below:

About firmware updates for AirPods - Apple Support (BH)

There is no way to force update of AirPods firmware. Make sure AirPods are charging and your iPhone is close.

When you let case open for a while it should update, just open it, on phone you will se battery % and leave it like tat for a few minutes