On the technical side, the app now features the same Portraits Effects Matte technology found in the iPhone XR. That technology allows the single-lens to create Portrait mode images. And now it can be used by all iPhones with Halide.
Those results should feature more detail and a better depth of field rendering.
Another major new feature for all iPhone users is the revamped landscape UI. Photographers can take advantage of updates gestures and view EV/manual shutter time displays and other smaller ergonomic updates. The UI is also further tweaked for the 6.5-inch screen of the iPhone XS Max.
Also, the new Technical Readout feature will show you all of the available data about your current iPhone camera.
Halide Camera is designed for the iPhone. It can be downloaded now on the App Store for $5.99.