One important option is missing in Tinode's applications - a possibility to hard delete message for sender and recipient within 3, 4 or 5 minutes of sending.

I am using Whatsapp and al least once a month somebody me sends a message that was intended for another person. Whatsapp permits to delete messages "for all" and its very good because it's about privacy.

If somebody inadvertently sends a message to someone wanting to send it to another person, and if a message contains some confidential information, it's a big problem because there is no way to delete such a message.