Telegram has added a number of new features. From Telegram version 5.10 and later you can use slow mode in groups, send silent messages.
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How slow mode works on Telegram
Slow mode is a new option that limits the speed at which people in a group chat can send messages. Once a group administrator enables Slow Mode, members will have to wait a certain amount of time before sending one message after another. This ranges from 30 seconds to an hour.
Group admins can keep Slow Mode enabled permanently or turn it on at certain times. Slow mode can be enabled and disabled in group permissions. Once enabled, members will see a countdown timer informing them how long they have to wait to send another message in the group.
How silent messages work on Telegram
They allow you to text someone silently, even if they don't have Do Not Disturb mode enabled. All you have to do is hold the Submit button until you see the option Send without sound.