Apple announced the next major update to iOS at WWDC 2017 today, calling it, you guessed it, iOS 11. Three devices will lose support, making the OS exclusive to 64-bit devices, and while the company didn't explicitly say so during its keynote, 64-bit apps.
The first Developer Betas are out, and 32-bit apps are not supported. It won't be coming back either, as the release notes explicitly say that the apps won't run on future versions.
Developers that want to target 32-bit devices can still do so. They'll just need to target those apps for iOS 10, and of course they'll need to include a 64-bit build with the submission.