Make an app behave as if it is on kitkat

I have an app that worked well on my i9100 (Samsung Galaxy S2) with a custom Kitkat rom. Now, I have installed CM12 (Lollipop) and this app isn't working as it should have.

It shows a login screen, clicking "sign in" on which it throws an error - which didn't show up when the phone was on Kitkat.

Is there a way whereby I can tell the app that it is running on kitkat or run an app in compatible mode(?)