Apple has just released iOS 12.1.4 for iPhone, iPad and iPod Touch. This update fixes a shameful bug that was discovered a little more than a week ago. Due to this bug, it was possible to activate the microphone or camera of contacts without having to record them.
As this was a serious privacy issue, Apple temporarily turned FaceTime off for groups. After the update to iOS 12.1.4, it is however again possible to have a group conversation via FaceTime.
In the first phase, the vulnerability was identified by a 14-year-old in the United States. When he tried to contact US company officials to report the issue, he was blatantly ignored because of the complicated policy of the Cupertino giant on the subject.
FaceTime for groups was preventively disabled on January 29th. Apple promised another solution in the same week, but could not make it happen. Now, a week and two days later, there is still an update. You can install iOS 12.1.4 on your iPhone or iPad as usual by going to Settings → General → Sofware update.