There has been increasing discontent amongst iPhone 12 buyers, with reports that they have not quite received what they are paying for.
Specifically, iPhone 13 owners did not see a noticeable increase in the refresh rate of the smartphones, with the screen still appearing to refresh at 90 Hz, despite one of the major features of the update being a new 120 Hz display.
Those who defended Apple has said that the iPhone 13 features an adaptive refresh rate that does not hit 120 Hz in most situations, thereby increasing battery life, but many others felt there was something more fundamentally wrong.
Apple has now admitted that fixes are indeed needed via an OS update, as Core Animation-based apps have a bug that limits frame rates.
More significantly, all your other apps will also need to be updated, as developers need to specifically unlock 120 Hz support via a key in the .plst file manifest. This may be an issue if you are using orphaned apps that are no longer supported by the developer.
Apple told iMore they will be pushing out an update to iOS 15 in the future to address the issue.
See YouTube channel Golden Reviewer illustrate the issue in his video below: