Connection drops on iOS 11
On iOS the connection between iPad/iPhone and Control Unit might be dropped after ~90 seconds (on both the original app from Carrera and SmartRace). This is explicitly no issue with the app, but is caused by an incompatibility between the AppConnects firmware and iOS 11.
Carrera has confirmed that early charges of AppConnect are affected and they need to be sent to Carrera in order to have the firmware updated. An official statement of Stadlbauer is available confirming the issue and the procedure (available here, unfortunately only in german). Please contact your reseller for more information on the exact procedure.
Update December 2019: User Andrew R. managed to get his AppConnect dongle replaced by contacting Carrera directly. Just send an email to email@example.com, include the year of the purchase and your shipping address and ask for a replacement. You should receive a more or less immediate reply from Carrera of America.