added check for at least iOS 9.0
This closes #24
diff --git a/src/ios/CDVWKWebViewEngine.m b/src/ios/CDVWKWebViewEngine.m
index 5d361c5..0985316 100644
--- a/src/ios/CDVWKWebViewEngine.m
+++ b/src/ios/CDVWKWebViewEngine.m
@@ -99,7 +99,7 @@
wkWebView.UIDelegate = self.uiDelegate;
self.engineWebView = wkWebView;
- if ([self.viewController isKindOfClass:[CDVViewController class]]) {
+ if (IsAtLeastiOSVersion(@"9.0") && [self.viewController isKindOfClass:[CDVViewController class]]) {
wkWebView.customUserAgent = ((CDVViewController*) self.viewController).userAgent;
}