Amazon has rolled out several substantial updates to its Kindle e-readers in recent months, introducing some useful new features. In June, it released an update that added new spacing options for words, characters, and paragraphs. In August, it launched another update that introduced a new Assistive Reader feature to Kindles, which reads books aloud like an audiobook, along with a new font option that enlarges the Kindle's user interface to improve visibility.
Beyond that, Amazon hasn't disclosed any additional changes in this update, although it's always possible that some new features may not have been discovered yet. That said, there is widespread speculation that the main reason Amazon released this update wasn't to add new features to its Kindle e-readers, but to strip away a popular functionality from them by patching a new jailbreaking method that has been gaining popularity.
Has Amazon patched the AdBreak jailbreak method?
It hasn't been confirmed by the Kindle Modding Wiki, but it appears to be the case
A few weeks ago, a new Kindle jailbreaking method called AdBreak was released by members of the Kindle Modding Wiki, exploiting a vulnerability in the ads displayed by Amazon on some of its Kindle e-readers to jailbreak the devices. Yes, that's right -- Amazon's ads are the main reason people have been able to jailbreak their Kindles over the past month or so.
The jailbreak worked on most Kindle models, except the Kindle Colorsoft or the Kindle Scribe, due to their lack of ads to begin with. Given that the jailbreak worked on a vast majority of Kindles, you can imagine Amazon wasn't too pleased by the fact that people were liberating their Kindles in droves, and likely wanted to put an end to it.
There's a strong possibility that with this latest Kindle update, version 5.18.6, Amazon may have done just that. While it has not been confirmed yet by the Kindle Modding Wiki, according to multiple posts from users on the MobileReads forums, Amazon has indeed patched AdBreak with this update, and speculation on Reddit also points to the same conclusion.
"Its main 'feature' is probably to block the latest jailbreak exploit," one Reddit user commented about the update, with another saying, "So this is obviously to counter AdBreak."
...if you're interested in jailbreaking your Kindle but haven't gotten around to it yet, you might want to consider putting it in airplane mode...
On the Kindle Modding Wiki, AdBreak is listed as "possibly" being patched after software version 5.18.5.0.1, so I'd be surprised if Amazon didn't fix it with 5.18.6, considering how widespread the jailbreak has become since its release in late September.
Of course, Amazon's patch notes for the update simply state that it has implemented "bug fixes," and the company would never confirm that it has actually fixed a massive jailbreak, which was admittedly embarrassing for them due to how it used its own ads against it.
That said, if you're interested in jailbreaking your Kindle but haven't gotten around to it yet, you might want to consider putting it in airplane mode to prevent the latest update from being downloaded. Otherwise, if 5.18.6 is installed, you will likely be unable to get AdBreak to work.