Apple releases another new slight AirTags firmware revision
Just eight days after releasing the last AirTags firmware update, Apple has done it again.

AirTag firmware updated
It is unknown what the new firmware with version 1.0.291 (A1291e) brings, and Apple has released no documentation to support the revision. However, the update is expected to bring bug fixes and general improvements to the product.
The past firmware was upgraded to the same version number but with a different build number -- 1.0.291 (1A291c). The last firmware was released just five days after the previous one debuted.
To find out your AirTags firmware version, a user can go into the FindMy app. Tap on the Devices tab and tap one of the AirTags. Under the battery, icon tap on the device name to view the firmware version.
Unfortunately, there is no way to force an AirTags firmware update like users can update the operating systems of iOS, iPadOS, or macOS.
Read on AppleInsider

AirTag firmware updated
It is unknown what the new firmware with version 1.0.291 (A1291e) brings, and Apple has released no documentation to support the revision. However, the update is expected to bring bug fixes and general improvements to the product.
The past firmware was upgraded to the same version number but with a different build number -- 1.0.291 (1A291c). The last firmware was released just five days after the previous one debuted.
To find out your AirTags firmware version, a user can go into the FindMy app. Tap on the Devices tab and tap one of the AirTags. Under the battery, icon tap on the device name to view the firmware version.
Unfortunately, there is no way to force an AirTags firmware update like users can update the operating systems of iOS, iPadOS, or macOS.
Read on AppleInsider
Comments
This is a p*ss-poor way to update hardware, and I hope they find a more reliable method soon.
This quote is from an AI article in June, after the second (I believe) firmware update:
“ For instance, the new AirTag firmware version is 1.0.276 build number 1A287b, versus the old build number of 1A276d.”
https://appleinsider.com/articles/21/06/23/apple-has-released-slightly-revised-airtag-firmware
Incidentally, mine are all still showing .276 as well.
Checking it at the previous announcement of v.1.0.291 (1A291c), it showed 1.0.276. Yesterday I put another one is service and today, it shows v.1.0.225. I expect the remaining two will also show .225.
Since the day of the announcement of the .291 (c) update, I've kept the phone and my AirTag and phone practically as conjoined twins, but no joy. Maybe this second update (e) coming down the pike caused the first one to be pulled back.
I'm guessing neither of these updates hold any real benefit for me, so I've stopped obsessing about them getting updated.
But I discovered today that it had stopped reporting for a second time, and the last known location was from 4 days ago. I had to add it back to “Find My”.
Yesterday it did its “chirping” noise as it sometimes does when it is moved after not being near my phone a while, so I didn’t think to check.
Today, it’s not making any sounds at all, even after removing/putting back the battery to reset it.
Without any release notes it’s difficult to know if these might be problems being fixed by the firmware updates, or not.