AT&T is rolling out a new feature in its MyAT&T app intended to prevent nefarious individuals from accessing customers’ online accounts. Wireless Account Lock, which has been rolling out in waves but will reach wide availability on Tuesday, disables some key actions that are frequently used to circumvent a legitimate owner’s access to their account.

This type of access is different from large data breaches, such as the two incidents that AT&T has recently agreed to settle for $177 million. Wireless Account Lock adds a security step to keep someone from getting access to your account and doing things such as shutting you out or ordering hardware — on your dime — that is then shipped elsewhere.

A new Business Account Lock feature is also now active for corporate customers. AT&T prepaid customers can also engage an account lock with similar blocking features.

Crucially, only the primary account holder and any person on the account that they designate as a secondary account holder can control the Wireless Account Lock. That blocks others on the account from making important changes.

The Wireless Account Lock feature is accessible only through the MyAT&T app. On postpaid accounts, it works on any active AT&T device associated with the account. If that phone is lost, the primary or secondary holder can log in to the app using another device registered to the account. If one is not available, you’ll need to contact AT&T and go through a more rigorous authentication process.

What gets locked down by Wireless Account Lock

The lock feature is designed to protect against someone impersonating you to gain account access. When it’s enabled, the following features require the approval of the account holder(s) to be implemented:

• Changes to billing info, authorized users and phone numbers

• Transferring wireless numbers to other accounts

• Buying or upgrading a device on the account

• Swapping the SIM card or eSIM to another device

• Adding a new line

For the Business Account Lock, account administrators can control which lines are locked and can choose which lock features are implemented.

How to enable Wireless Account Lock

When signed into the MyAT&T app, do the following:

1. Tap the Services button (the icon with a grid of squares).

2. Tap Mobile security.

3. Scroll to the bottom of the screen and tap Wireless Account Lock, then tap Continue to get past the explanation of what the feature does.

4. Tap the checkbox after you’ve reviewed the terms and conditions, and then drag the Swipe to Lock slider.