cordova plugin add https://github.com/Telerik-Verified-Plugins/cordova-plugin-wkwebview-engine
appbuilder plugin add "Cordova WKWebView Engine" --release
Cordova iOS apps traditionally ran in a webview called UIWebView, a restrained version of the webview used in the Safari browser. A notable difference is the UIWebView embedded in hybrid apps doesn't have access to the fast Nitro JS engine.
With iOS 8 Apple released the WKWebView which doesn't have these restrictions, so all apps embedding a webview (every hybrid app out there) gain a performance boost!
That's good news, there is some bad news as well. The new webview has many differences (and even bugs) meaning it's not a trivial upgrade for most hybrid apps.
The worst issue is that WKWebView doesn't allow loading files from the file (file://) protocol like UIWebView does. This is what Cordova uses internally to load files from the www folder. Using an embedded local http server to load the www folder from the http protocol circumvents this issue.
Another major pain is that because of using the http protocol WKWebView must now comply with CORS. This means that if your app currently talks to a remote server over http (like a REST API), that server must allow access from your app (see below how to do this).
These and other issues mean Apache can't simply release a new version with WKWebView enabled by default, so they will likely provide a similar plugin, or add a configuration parameter to Cordova-iOS to enable WKWebView in a future release.
Note that a built-in Apache solution should make this plugin obsolete, but in the meanwhile this is the only way to use WKWebView in your Cordova app.