There is some hope
I used above url to download the Always on display app.
I got always on display option in display setting. I also got always on plugin in application manager .
Initially the always on display option is off but when i try to turn it on it says always on display has stopped. Im on stock unrooted rom with oct patch.
I hope AOD will be implemented in our s6 in future. Or if any developer can use that app to work it earlier..
Sorry for english