My wife got me a Leica C (Typ 112) last year. It's a 13-year-old camera, released in 2013, built on Panasonic internals. The official Leica app for iPhone doesn't support it anymore for wifi access.
So I made my own. Looked up the spec (it uses the Panasonic wifi protocol), got the connection working, and added features that never existed on the original: a live histogram and an intervalometer.
Mac app, waiting to connect. Join the camera's wifi network and hit connect.Connected. Live viewfinder at 30fps with a shutter button. Remote shooting from the Mac.Remote view with settings: flash, self-timer, filter. Live view through the curtains at 29fps.Gallery view on Mac. 50 photos on the card, thumbnails loading over wifi. Can download individual or all.Gallery on a card with fewer photos.
iPhone app. Gallery, remote viewfinder, and camera settings (ISO, exposure comp, white balance, drive mode).Connected on iPhone. The camera shows up as "oneonetwo". Gallery loading over wifi.
Works on iPhone and Mac. The app is in App Store review right now. Will update here when it's available.