Determining which frameworks use UIWebView
Apple has deprecated UIWebView and will not be accepting new apps with UIWebView starting April 2020 and app updates with UIWebView starting December 2020. If your app uses UIWebView you should replace it with WKWebView.
The check for UIWebView has already been implemented as a warning after a build submission:
ITMS-90809: Deprecated API Usage - Apple will stop accepting submissions of app updates that use UIWebView APIs starting from December 2020. See https://developer.apple.com/documentation/uikit/uiwebview for more information.
Removing UIWebView from your app might seem quite straightforward, but you probably use some 3rd party libraries and they might also contain UIWebView. You need to find all of them and update them, if available, or replace them. This process is not exactly trivial.
If you use 3rd party libraries as code, for example via Cocoapods, you can just do a text search for UIWebView in their sources.
For example doing grep -r 'UIWebView' . in RxSwift sources prior to 5.1.0 gives you a lot of results as RxSwift has included UIWebView binding before 5.1.0.
❯ grep -r 'UIWebView' .
./RxCocoa/iOS/UIWebView+Rx.swift:// UIWebView+Rx.swift
./RxCocoa/iOS/UIWebView+Rx.swift: extension Reactive where Base: UIWebView {
./RxCocoa/iOS/UIWebView+Rx.swift: public var delegate: DelegateProxy<UIWebView, UIWebViewDelegate> {
./RxCocoa/iOS/UIWebView+Rx.swift: .methodInvoked(#selector(UIWebViewDelegate.webViewDidStartLoad(_:)))
./RxCocoa/iOS/UIWebView+Rx.swift: .methodInvoked(#selector(UIWebViewDelegate.webViewDidFinishLoad(_:)))
./RxCocoa/iOS/UIWebView+Rx.swift: .methodInvoked(#selector(UIWebViewDelegate.webView(_:didFailLoadWithError:)))
./RxCocoa/iOS/Proxies/RxWebViewDelegateProxy.swift:extension UIWebView: HasDelegate {
./RxCocoa/iOS/Proxies/RxWebViewDelegateProxy.swift: public typealias Delegate = UIWebViewDelegate
...
If your 3rd party libraries come as a .framework file without sources, there is a different way to check for UIWebView.
You can use nm to get the symbols table of the executable in a .framework and do a grep there
❯ nm AWSDK.framework/AWSDK | grep -i UIWebView
U _OBJC_CLASS_$_UIWebView
U _OBJC_CLASS_$_UIWebView
0000000000002a00 S __OBJC_LABEL_PROTOCOL_$_UIWebViewDelegate
0000000000002998 D __OBJC_PROTOCOL_$_UIWebViewDelegate
0000000000002348 s l_OBJC_$_PROTOCOL_INSTANCE_METHODS_OPT_UIWebViewDelegate
00000000000023b0 s l_OBJC_$_PROTOCOL_METHOD_TYPES_UIWebViewDelegate
0000000000002330 s l_OBJC_$_PROTOCOL_REFS_UIWebViewDelegate
000000000000aaa0 S __OBJC_LABEL_PROTOCOL_$_UIWebViewDelegate
000000000000a858 D __OBJC_PROTOCOL_$_UIWebViewDelegate
0000000000005780 s l_OBJC_$_PROTOCOL_INSTANCE_METHODS_OPT_UIWebViewDelegate
00000000000057e8 s l_OBJC_$_PROTOCOL_METHOD_TYPES_UIWebViewDelegate
0000000000005768 s l_OBJC_$_PROTOCOL_REFS_UIWebViewDelegate
AWSDK.framework/AWSDK(UIWebView+LongPress.o):
...