Thinking about using Xojo for an IOS applicaiton that we currently have on Android would like to add an IOS version only limiting factor I can see so far looking at the Xojo IOS docs is there does not seem to be a way to access or list a users contacts. Is this possible with an IOS app written in Xojo?
With pure Xojo, sadly no.
You could try Christians AddressBookKit for iOS, but be aware it uses the ABAddressBook class that Apple discourages to use since iOS 10.11. It could stop working with a future iOS release.
Or youd have to declare into the Contacts framework yourself. As far as I know, there is no current solution available in one of the libraries.
Contacts framework is a no go for Xojo.
It needs multi thread safe code.