I don't care about 64-bit devices. I'm fine with them not being able to install or run the app, if that's how it is. People with 64-bit devices can easily afford better products that my app tries to replace. I don't own device to test the 64-bit version, and I don't know anyone who does.
I care about existing users. I kept minimum SDK version as low as possible so that my app might reach all the cheap phones in poorer parts of world. It actually works today across many different devices, so what has changed?