FCC filings for Apple's newly released AirTags have revealed that the Cupertino tech giant began regulatory testing and preparing to seek...
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So according to the FCC documents in this story the AirTag has firmware (and in this case it was running firmware 1A186).
From the videos I’ve watched on AirTag I can’t see any mention of firmware through the Find My app but it’s possible it shows up in Bluetooth settings like AirPods and just updates quietly in the background.
I'd say its possible, but unlike Apple's other products, it probably won't get any updates - Unless a catastrophic bug is identified. It has one job and as long as it does that one job, I'll probably not see much in terms of software updates