Incoming calls now wake the iPhone app and show on the phone's own call screen.
An office phone that only rings while the app is open is not much of a phone.
How a closed app rings
A phone will not let an app sit in the background listening for calls; the battery would be flat by lunch. Instead, when a call arrives for you, Kahevo sends a notification through the phone maker's service. That wakes the app, and the app tells the phone to show its own call screen.
So an office call now looks like any other call: full screen, on the lock screen, with the caller's name, answered with a swipe.
A race against the clock
From the moment the notification lands, the app has a few seconds to wake, connect and take the call. Meanwhile the caller is already hearing ringing. Kahevo holds the call's details for the app for up to a minute, so a phone that wakes slowly still gets its call. If the caller gives up in the meantime, the app is told that as well, and stops ringing.
The silent build
The first build connected every call in perfect silence, both ways.
The cause was a turf dispute. The phone's call screen switches the audio on and hands it to the app. Our audio was running in a separate part of the app that the phone treats as a different program, and it was muted while the call screen was up. Each side was sure the other was handling the sound.
They have since had a talk. The audio now runs in the app proper, where the call screen expects it.
An extension that is always home
One side effect we like: an extension with the app counts as reachable even when the phone is in a pocket. A call rings for the usual time and then goes to voicemail, the same as for a desk phone nobody picks up.
Where it stands
In testing, on our own phones first.