Board Thread:Game Discussion/@comment-28169398-20171102025118/@comment-28169398-20171110171037

The problem is with Apple. Other Apps, games not developed by Firemonkeys and those that use gyro, such as the Spirit Level or the Compass are significantly affected as well.

The likelihood is they changed the chipsets for gyros in newer devices and wrote code that degraded the performance of legacy hardware. 11.1 could be optimized for iPhone 8 and X and that may have been why the problem was so evident.

Also iOS updates are firmware updates, which are specific to a certain model of iDevice. Apple is likely not immune to cut and paste dev either and they likely didn't test the changes on legacy devices.