Apple is rolling out a new version of its AirTags firmware. The refreshed firmware has a build number of 1A301, up from 1A291. While there is no way to force your AirTag to update its firmware, there is a way to see if it has been updated to the latest version.
The rollout of the new firmware is a staggered one, with 1% of AirTag users receiving it today, 10% on May 3, 25% on May 9, and it will go fully live to everyone on May 13.
AirTag firmware updates install automatically when an AirTag is in range of your iPhone. The process is similar to how Apple updates the firmware of its AirPods lineup.
Checking your AirTag firmware version is a bit roundabout.
If your AirTag has not yet been updated, be patient. Just make sure your AirTag is in range of your iPhone and it will automatically update when the time comes.