Apple has now released its first firmware update since the AirPods Pro went on sale, with a new firmware version number 2B588, replacing the 2B584, which has been pre-installed since its release at the end of October. This firmware update affects Only AirPods Pro, not AirPods. Because Apple did not provide release notes for its AirPods Pro firmware update, it is not clear what exactly was updated, but a relatively small change in the build number indicates that it may have been fixed or adjusted for performance.
The user does not need to do anything special, and the firmware is automatically updated when the AirPods Pro is placed in the included charging case, which is also charging and within the range of the iOS host device. The firmware is automatically applied when you connect the AirPods Pro to your iPhone or iPad. There is no update mechanism available to force updates to the AirPods Pro on hand, but you can check the firmware version number of AirPods Pro in Settings- Universal.