Different build settings.

Friendly hint: Better to add at least some basic details to your question here, rather than expect people to spend time following a link.

To add a Swift Package: File > Add Packages... Then specify the Swift Package you want to add

Friendly hint: It's very hard to make any sense of code screenshots. Better to put your code into a code block (using "Paste and Match Style"), to make it more readable. Then people may be able to help you.

To format the code correctly, you need to paste it into the original question, or a new reply, not a comment.

scanf_s is specific to Microsoft compilers, so you won't find it in Xcode. Since scanf_s is Microsoft's "improved" version of scanf, you might try using scanf instead.

For a limited time, you should be able to edit your question, so that it makes sense.

You can use your installers to create bootable usb installers (using the "createinstallmedia" command). A quick trawl of the Internet will show various guides. It may not be wise to downgrade over a newer version... I suspect erase-and-install would be the safest option.

A quick search of this forum will show that your question has already been asked (and answered) lots of times.

Comments from my personal experience of transferring a couple of apps... 1 as long as the criteria are met for the transfer then there shouldn't be an issue with the transfer. Correct. 2 Once the transfer is initiated how long should the transfer process take? I found it to be quite quick. 3 Once the transfer process is completed... The app remains available for sale at all times. 4 ...the app that is being transferred was built in Swift 3, should this have a bearing on whether or not the app can be transferred... This is not an issue, as the app transfer does not involve resubmission.

If your problem is more complex than your original question, you will need to add more information. e.g. Current macOS version? Target macOS version? What are your "installers"? e.g. "Install macOS Catalina.app"? creating an installer on an external device doesn't work "Doesn't work" how? Can't create installer? Can't boot from installer? Can't run "Install macOS xyz" from installer? Installation starts, but fails? I mentioned bootable usb installers... that's not just any "external" installer.

I found the app transfer process to be fairly straightforward. After an app transfer: The app is transferred to your dev account The Bundle ID stays the same (and becomes yours) The App ID Prefix changes (from the previous developer's Team ID, to your Team ID) Xcode Signing & Capabilities: "Team" should show your dev Team "Bundle identifier" should be the same as before the transfer Nowadays, I generally let Xcode automatically handle all of the Certificate/Profile side of things, but you can still do it manually, if you prefer.

This is the Apple Developer Forum. You can use the Maps app to send feedback about issues in Apple Maps. (A quick Google search will show a guide, if you can't figure out how.)

Can you post an example, so we can see what you mean?

Do you have a question?