[stunt]

It isn't by default. You have to enable it yourself.

[GranPC]

This is wrong. All communication is encrypted in transit, even for non-secret chats.

[justaj]

Is it also E2E encrypted though? If not, wouldn't that mean that Telegram servers could snoop in on the non-E2E conversations?

[usrnm]

You're talking about "secret chats", the Telegram way of doing E2E, but it doesn't mean that all other communications are sent or stored plain text. And there is no setting in the app to enable encryption (I just checked), because there is no way to disable it. "Not E2E" != "not encrypted"