When I send multiple push notifications, I need them to be all shown in the notification bar ordered by the time sent desc. I know I should use unique notification - I tried
You need to set either a unique tag (String) / id (integer)
Checkout this method in official documentaation
I suggest using any timestamp (SystemClock.uptimeMillis() / System.currentTimeMillis()) as a tag while notifying.
notificationManager.notify(String.valueOf(System.currentTimeMillis()), 0, notification);