I thought that if I write a new app as an upgrade for an old app and have the same bundle identifier, when I uploaded it, it would automatically go to the original app. I was wrong! I have just loaded up a new app to the App Store. Can somebody tell me how to proceed so that the new app becomes an update to the previous app?
Wrote a new app but wanted it to be upgrade of oler app?
Don't you have to have created a new app in App Store Connect for Xcode to upload it? Otherwise, Xcode doesn't know where the app should go.
Not sure how you achieve this, but before making any more attempts at uploading to App Store Connect, install your old app on the Simulator, then run the new app and install it to the Simulator. If you get two different apps, then you know that you haven't done it properly. Delete the new app from the Simulator, make some changes in Xcode and install to the Simulator again. Repeat until it actually just installs over the top of the original app.
Maybe I miss something in what you are trying to do.
Why do you need a new app ?
Why not just completely rewrite the code within your older app: that will de facto be a new app.
There is nothing that prevents you for doing so and from a user perspective that will be a - significant - upgrade.