Apple today released a new firmware update for the original AirPods Pro, the AirPods 2, the AirPods 3, and the Lightning version of the AirPods Max headphones. The new firmware is version 6F21, up from the prior 6A326 firmware that these devices were previously running.
There is no word on what's included in the firmware, but given that these are all older models, it is likely that the new firmware includes bug fixes and other minor improvements.
Apple doesn't have a way to manually upgrade AirPods software, but firmware is generally installed over-the-air when the AirPods are in a charging case and connected to an iOS device or Mac.
Source: Macrumors