MacRumors:

Apple today released a new firmware update for the AirPods 2 and the AirPods Pro, though there is no word on what’s new in the refreshed firmware.

‌AirPods Pro‌ were previously using firmware version 2B588, while ‌AirPods‌ 2 were previously using 2A364. Both ‌AirPods Pro‌ and ‌AirPods‌ 2 run firmware version 2C54 following the update.

As far as I know, there’s no way to force a firmware update, but it’s delivered, at some point, over-the-air, when you connect your AirPods to your iOS device.

To check your firmware version#:

Settings > General > About > [Your AirPods Name]

Note that your AirPods won’t appear in the list until they are connected.