What Apple iOS versions does ForeFlight support?

Minimum iOS Version: 

The current minimum iOS version supported by ForeFlight Mobile version 11.0 (January 2019) and later is iOS 11. Devices that are not running at least iOS 11 will not be able to update the app beyond version 10.6.

Older iPads that cannot be updated beyond iOS 9.3.5 can still continue to use ForeFlight Mobile 9.6.