I\'m in the progress of migrating my app from UIWebView to WKWebView. All is going well and working as I tinker more with it. However, I notice now that I can\'t download forum
You are probably downloading a not-authorized page because your WKWebView and HCDownload instances don't share cookie sessions like UIWebView could. That's a necessary trade-off for the WK2 process model's speed & security improvements.
I added downloading to my WKWebKit-based OSX/Swift mini-browser by implementing _WKDownloadDelegate. Its a totally undocumented private protocol as of El Cap and iOS9. It lets your navigation delegate call decisionHandler(_WKNavigationResponsePolicyBecomeDownload)
whereby WebKit will download in the background after giving you the chance to pick/change a file name. I haven't the foggiest idea on how to implement a file picker in iOS yet, nor if using that protocol would be allowed by the App Store reviewers. But my app now does correctly handle downloading from session-authentication sites like your PHP forum.