It's not clear to me that these changes make an app like this impossible. There would be a lot of implementation churn, and maybe some user visible differences, but I think the main issue here is they don't want to spend the time to rewrite the app, and maybe there's some fear of future changes breaking it again. Which is totally fair, churn sucks. But on the other hand there are real, serious security issues motivating these changes that should not be minimized.