In WWDC19, Apple announced the support for Swift Package Manager for all of Apple's platforms, including iOS. I know it will work with Xcode 11 for iOS 13, but I have only found limited findings regarding the details around it.Will we be able to use SPM for our apps/SDKs if we have a deployment target before iOS 13?Integrating .xcframeworks with SPM will work for integrators on Xcode 11. However, will they be able to create apps using .xcframeworks for devices that are on pre-iOS 13?Regarding normal .frameworks and SPM, will we be able to use SPM to host .frameworks that will be used on devices that are on pre-iOS 13?Are there any misc concerns to watch out for if my SDK is in Objective-C and I wish to create a framework and put it into SPM?