Some Sprint users reporting connectivity issues with their iPhones following installation of iOS 12.1.3

Following Tuesday’s release of the iOS 12.1.3 update, a number of users have reported a bug in which cellular data connection is either permanently disabled or extremely spotty following the initial installation and reboot of iOS 12.1.3.
The same situation also happened following the release of iOS 12.1.3 on Christmas even, albeit the update was launched to fix a random cellular data killing bug.
In this case, it doesn’t seem that a simple reboot fixes this bug. While some sites recommend a full-fledged Reset Network Settings route, it’s not a confirmed fix and you’ll be stuck reentering Wi-Fi passwords again, so unless you’ve really hit the wall, it’s recommended that you hold off on the update.

According to a post on Reddit and a couple of tips in our inbox, the issue seems to primarily affect Sprint users, though one tip reports the same problems in Canada. There doesn’t seem to be a rhyme or reason regarding specific phone models, and the issue could affect devices from the iPhone 6 through iPhone XS.
The two tips that have been corroborated is that Sprint users appear to be seeing more of the connectivity error.
Apple’s Twitter support team has also reached out to users regarding the issue.
If you’ve seen this issue on your end following the installation of iOS 12.1.3, please let us know about your experience in the comments section.
Via 9to5Mac, Reddit, and Twitter