Can anyone suggest what to do about this message that I get when submitting my Xamarin Forms app to the iOS store?
This is a known issue which was recently closed by the Xamarin team issue can be found here https://github.com/xamarin/Xamarin.Forms/issues/7323
And the fix is and i qoute
All the bits are in place, solution time! TL;DR: all is described in this piece of documentation here.
Make sure you are using the latest Visual Studio (for Mac) on the stable channel, that should put you on the right path. At the moment, you will need to use the Xamarin.Forms 4.5-pre1 preview release. I understand that this might not be an option for all of you, but rest assured, the stable package will be out well before the deadline. Stable 4.5 is planned mid to end of February.
Lastly, put the
--optimize=experimental-xforms-product-type
flag into your iOS additional mtouch arguments setting and you should get rid of the deprecation warning by Apple. If you don't have any references of your own to UIWebView of course