I believe there is a program called imazing that will pull it from your current iPhone and allow you to install it on the new phone. You can go to his website on how to do it. Think there is a page here discussing it.
As long as you have both devices and use the same apple account it still works. Where it goes sideways is people who trade in the old device before they make the backup.
ETA:
I will add a caveat on function. iOS and the hardware has changed since the sanction. Trying to connect a D3 Drop or Kestrel 5700 to Strelok will just crash the app now. Otherwise it works fine.
As long as you have both devices and use the same apple account it still works. Where it goes sideways is people who trade in the old device before they make the backup.