From Xojo Documentation

Property (As LargeTitleModes )
aiOSView.LargeTitleMode = newLargeTitleModesValue
LargeTitleModesValue = aiOSView.LargeTitleMode

New in 2018r2

Supported on Mobile (iOS).

Enable and controls how titles render in iOS 11+ using the LargeTitleModes enumeration, which has these elements: Automatic, Always, Never (the default). This property does nothing on pre-iOS 11 versions. Available in 2018r2.

Sample Code

Enable large titles on the view:

Self.LargeTitleMode = LargeTitleDisplayModes.Always