onPartialUpdate is not called on fr735 (simulator and device)

OK, now I know and simple fix settings...

Vanu is normal thing - rather due to AOD than hardware possibility.

It's not just the CIQ level.  It's the hardware on the actual device.  If you look at the list of supported forerunners that have onPartialUpdate, this is it. 

Forerunner® 245
Forerunner® 245 Music
Forerunner® 55
Forerunner® 645
Forerunner® 645 Music
Forerunner® 745
Forerunner® 935
Forerunner® 945
Forerunner® 945 LTE

You'll also notice that none of the Venu devices are supported and they are CIQ3 or CIQ4.  Also the va-hr isn't supported, as it was around the same time as the fr735.

You can use jungles for this, or just make use of the "has" I posted here. 

Here's a whole thread I started 5 years ago about 1hz/onPartialUpdate with a sample project you can try any target and see how things are handled on devices like the fr735: https://forums.garmin.com/developer/connect-iq/f/discussion/5156/1hz-watch-faces---q-a

I've read about it but it was for CIQ 1.4 and didn't  expect it possible for 2.4.

And this again problem with not clear connection with ciq/sdk/level/devices but no way, everything come out in reality...

If you look at the API documentation that's included with an SDK, and check out onPartialUpdate, you can expand "Supported devices" and see which devices support the call. 

The oldest device that does is the Fenix5.

The fr735 doesn't have the hardware required for onPartialUpdate.  A device needs a display where only a part of it can be updated, and with the fr735 it's always the full screen.

You can check if a device supports onPartialUpdate with

if( Toybox.WatchUi.WatchFace has :onPartialUpdate ) {}