Google today, via AdMob, sent an email to the app publishers saying that all the GMA SDK versions including and after 7.55.0 released on Feb 4th, 2020, default to WKWebview and have removed UIWebView entirely.
Publishers, that want to comply with App Store’s requirement, should update the Google Mobile Ads SDK, and publishers using AdMob mediation or Open Bidding, should review the latest minimum SDK of 3P ad networks that utilize WKWebView.
Apple last year announced that this year will stop supporting apps using web content using the deprecated UIWebView API. The App Store no longer accept new apps using UIWebView as of April 2020, and it will stop accepting app updates using UIWebView as of December 2020.
Apple suggests that developers update to WKWebView as soon as possible for improved security and reliability. WKWebView it is also supported in iOS and macOS, and by Mac Catalyst.
UIWebView has been deprecated by Apple since June 2018. UIWebViewis a user interface control used in iOS applications, and it allows a developer to add web content to their apps.