The release of iOS 11.2 last week was intended to fix a number of bugs plaguing Apple’s mobile operating system but it, at least for iPhone owners on Sprint’s network, appears to have made things significantly worse.

Since the update became available, Sprint customers have been flooding social media and online forums with complaints that Wi-Fi calling no longer works when running iOS 11.2 and carrier settings version 31.0.

Wi-Fi calling typically allows a user to place and receive calls on a device via a Wi-Fi connection, even when the cellular network has poor reception or is not connected.

The issue has spared no iPhone user on the Sprint network. Complaints have identified the issue affecting just about all active models of iPhones that support Wi-Fi calling and are capable of updating to iOS 11.2, including the new iPhone 8 and iPhone X.

Thus far, it’s unclear if the issue stems from a bug in iOS 11.2—which Apple pushed out earlier than expected to deal with a significant issue that was causing iOS devices to get locked in a restart cycle—or if it is caused by the updated carrier settings. It is worth noting that other major carriers—including AT&T, Verizon and T-Mobile—do not appear to be affected.

A poster in the Sprint community on Reddit relayed their experience with the issue, explaining that prior to the iOS and carrier settings update, the device would turn on Wi-Fi calling “within seconds of my phone connecting to my router.” After the latest update, the user reported, “it takes hours, and in some cases not at all. Usually if left overnight the phone will eventually connect, but as soon as you disconnect/reconnect to the WiFi network it’s gone again.”

Apple and Sprint have not addressed the issue publicly, though a Sprint employee posting in the company’s forums provided some information. The employee said that a “temporary patch” was being tested on one of the Wi-Fi calling servers, and would be rolled out to more servers if it proved effective.

However, the Sprint employee had no information to provide regarding what was causing the issue. “In all of this I was not made aware of the problem being caused by the Carrier bundle, or iOS directly,” the employee wrote.

Some users have managed to work around the issue by downgrading their device from iOS 11.2 to iOS 11.1.2. Doing so reportedly makes Wi-Fi calling functional again. Downgrading the carrier settings to a previous version has not worked to restore the feature for users.

How To Downgrade To iOS 11.1.2

For those who want to restore Wi-Fi calling, downgrading to a previous version of iOS will be required. This is only possible to do with IPSW file, which Apple uses for iOS and firmware updates. It’s possible to get an IPSW file from sites like .

Once the user has acquired an IPSW file that fits their phone model and carrier, it is possible to restore the device to that version of iOS.

To do so, connect the iPhone to a computer via Lightning cable and open iTunes. Click on the device’s page in iTunes. Then hold down the Option key on Mac or Shift key on PC and click the “Restore iPhone” button.

Clicking while holding Option or Shift should cause a browser dialog box to pop up. This allows the user to pick a file to restore from. Find the downloaded IPSW file and click it. This will restore the device to that version of iOS.