[omh]

I've been asking the vendor the same question!

They seem to think it's not a drop-in replacement and don't want to rework their code to deal with the changes. I'm not sure to what extent this is Microsoft making compatibility hard or just a lazy vendor.

[adzm]

It is a completely different API compared to WebBrowser/MSHTL. It is akin to using CEF (Chromium Embedded Framework) for the most part. This can require rewriting pretty much everything that interacts with the browser currently as well as dealing with a completely different threading and event model in the new APIs (both WebView2 and WebKit/CEF/etc)