Gregory's Server@fritzoids @rachaelspooky you probably don't want to hear this, but it is not safe to do your banking on an old out of support android device. The bank is actually doing you a favor by requiring something newer.
You might be able to get away with a Chromebook. They support android emulation and you can run most android apps on them. If that works, you won't need a smartphone and you'll be able to keep a more familiar laptop interface.
@teddy
Oh, I am very aware of why they are requiring newer Android versions and that it is a good thing. I'm just disappointed that their response to "is there a WebApp?" is "nah, we like our apps and don't think we'll ever offer anything that'll run on the MacBook that actually will update. Or on the Windows desktop or the Ubuntu desktop that you have."
I do not like the small screens they don't lend themselves well to very much besides scrolling.