The feature added in the iOS 11.3 beta worked with Touch ID but not Face ID.

In the iOS 11.3 beta, parents and other "family organizers" are now able to approve purchases through iOS' "Ask to Buy" feature using Face ID on the iPhone X. This addresses a prior complaint from users who upgraded from Touch ID iPhones to the iPhone X with Face ID.

Previously, iPhone X users had to manually enter their passwords via the iPhone X's keyboard to approve any request from a child to download an app or make an in-app purchase, whereas other iPhone owners could use Touch ID. It might not seem like a major inconvenience to some, but some parents with several children, all of whom have iOS devices and are playing games that involve frequent, small in-app purchases, went to Apple's forums to complain about the constant hassle.

Apple promoted Face ID as a complete replacement for Touch ID when the iPhone X launched. In fact, third-party apps that used Touch ID could authenticate with Face ID automatically, with no action required on the part of the developer in most cases. We found when reviewing the phone that Face ID could be used to make other kinds of purchases, so it was perplexing to users when this one feature輸sk to Buy謡as not supported.

While the feature is not documented in Apple's iOS 11.3 beta release notes, 9to5Mac tested Ask to Buy with Face ID in the beta and found that it now works as expected. The publication reports that the first Ask to Buy request requires password entry, but iOS then asks users if they want to use Face ID in the future. If they opt in, subsequent purchases can be approved using the phone's facial recognition feature.

iOS 11.3 will be released widely to the public this spring, but its first public beta preview launched last week. The update features a significant update to ARKit, the software development framework used to create AR apps. It adds features to increase transparency of and offer options for dealing with the deliberate performance throttling that users experience after their batteries age on some iPhones.

It also adds health records to the Health app, a Business Chat feature for talking with customer support through the Messages app, the option to free up space by storing the content of the Messages app in iCloud, new Animoji, and new in-home streaming features with AirPlay 2.