Comment by emptysongglass

That user and the user you are replying to are not misinformed. They are perfectly correct.

Telegram does not store messages in plaintext. Period.

No matter how shrill the cries from Moxie Marlinespike and his adherents, E2EE is not the only form of encryption.

MTProto 2.0 is fully documented and everything the user linked described is true.