In macOS 10.14 the user can select between light and dark mode and can also select from a choice of 8 accent/highlight colours.
In IOS 13 the user can select between light and dark mode but the accent/highlight colour is either mode appears to me to be fixed to blue (or at least I haven't so far worked out how to change it).
Does anyone know if the accent/highlight colour on IOS is likely to change in the future to a user choice as in macOS, because I would like to be able to use this colour in my app.
Is the (currently fixed blue) accent/highlight colour for IOS 13 accessible and is so how do I get access to it as a colour, from Objective C?
The blue you are seeing is iOS' default tintColor. You can set that on a view basis or, if you want to override it app-wide, set it on your UIWindow. If a view doesn't have a tintColor explicitly set, it uses the tintColor of its superview—all the way up to the window.