Amazon has begun sending emails out to owners of its Echo Buds true wireless earbuds, cautioning those customers to update the device firmware as soon as possible to avoid a “potential safety risk.”

“We recently determined that in rare cases it’s possible for Echo Buds to overheat while in the charging case,” the email says. According to Amazon, the latest software update eliminates this issue and “improves the long-term performance of Echo Buds’ batteries.” Android Central first reported on the email. Amazon is urging anyone who purchased the Echo Buds for someone else as a gift to give them a heads up about this situation.

Amazon’s investigation into the matter was prompted by a customer report about the Echo Buds overheating while in their case. There have been a limited number of cases so far, and no injuries related to the overheating problem have been reported. Amazon declined to specify exactly how the Echo Buds reacted while overheating, such as whether they smoke, melt, potentially catch fire, or simply become uncomfortably hot to the touch.

“The update makes the device more efficient, and monitors performance to optimize how and when it is charged. Both improve the long-term health of the battery,” an Amazon spokesperson told The Verge by email.

As long as you have firmware 318119151 or above, you should be in the clear. To check what software your Echo Buds are running, open your Alexa app and go to Devices, then Echo and Alexa, then Echo Buds, and finally pick “About.”

Amazon automatically applies updates when your Echo Buds are paired to your phone. But if you don’t have the latest update yet, here’s how to initiate it:

· Open the lid of the case with the Echo Buds inside and confirm that they are connected to Bluetooth on your phone and the Alexa app 

· Check that your Echo Buds and case are at least 30 percent charged

· Close the case lid with the Echo Buds inside, and keep within Bluetooth range of your phone for 30 minutes

· Check that the software version is 318119151 or higher, following the instructions above

It seems that, in some circumstances, the Echo Buds were charging a little too intensely while in the case. The earbuds provide up to five hours of continuous battery life, totaling 20 hours when you include case recharges. You can also charge them for 15 minutes to get up to two hours of listening time. None of that really stands out as unusual or technically impressive compared to the competition. The Echo Buds charge via Micro USB.

Amazon’s earbuds offer hands-free access to the company’s Alexa voice assistant, and they also feature Bose noise-reduction technology. Though they didn’t quite make our wireless earbuds guide, the Echo Buds have remained a very good buy — so long as they can be used safely

The Echo Buds currently show a delivery date of August 14th on Amazon’s website. At least for now, that page doesn’t make any mention of the overheating issue.

Update July 15th 12:48PM ET: The article has been updated with more details around how Amazon became aware of the overheating issue.