Update existing app to work with most recent iOS

Job ID: 32343216

Budget: $15 – $25 USD

I have an app that was developed in 2016 and and for first 3 years it was working on all iOS devices without crashes. A year ago it started to crash on some newer devices and now it crashes on all devices.
The app never been updated since the first release. Original developer is gone out of business and I'm looking to work with someone who can use existing xcode files and see what needs to be done in order to fix all issues. I am an original creator of my app.