(Emmanuel Dunand/AFP/Getty Images)

Amazon is one of a slew of tech companies backing Apple in a legal fight with the Justice Department, which wants Apple to help it bypass security features on an encrypted iPhone. But late last year, Amazon quietly backed away from offering the type of encryption at the heart of that dispute by tweaking the software that supports many of its own consumer devices.

Fire OS 5, the latest version of the operating system used on Amazon Fire mobile devices, no longer supports device-level encryption -- a digital protection that only allows a person who knows the password or PIN to unlock a device to access the information stored on it. (Disclosure, Amazon chief executive Jeff Bezos also owns The Washington Post.)

Some customers began noticing a problem when their devices couldn't be upgraded to Fire OS 5 without removing the encryption. "How can we keep using these devices if we can't actually secure the large amount of personal data that ends up on them?" one wrote in a post on an Amazon forum in January. The retailer's move gained more attention this week.

When asked about the change, an Amazon spokesperson said that the company had "removed some enterprise features" it found customers "weren't using" when it released Fire OS 5 last fall.

Unlike Apple, which has made device encryption the default in its latest mobile operating systems, users of Amazon's products had to decide to turn on the feature. A page still up on Amazon's website describes how users could set it up -- and why it could be important.

In theory, Amazon devices that run older versions of the software can still encrypt. But newer products, or devices that have been updated to Fire OS 5, lack the option to turn on a feature that could prevent law enforcement or thieves from easily accessing data stored locally.

That's sending Amazon in the opposite direction of Apple and Google, which is also pushing device-level encryption as the default in the latest standard version of Android.

Update: Late Friday, Amazon said it will "return the option for full disk encryption with a Fire OS update coming this spring.”