New apps will fail to upload to the App Store Connect if the UIWebView API is included.
On the other hand, it was announced that the update deadline for existing apps would be "December 2020".
Reference link: [iOS] UIWebView is finally crazy ("ITMS-90809: Deprecated API Usage" email arrived) [Breaking news] [iOS] The deadline for UIWebView to be unavailable has been announced [IOS] How to find out which library contains the UIWebView API
About this, in Apple Developer News
Extend the update deadline after the end of 2020. We will inform you as soon as the official deadline is decided.
Was announced.
I don't know how long it will be extended yet (as of November 06, 2020), but there is no doubt that it is better to respond early. .. ..