Can someone read my WhatsApp messages from a device I used to own?

[AC Question]

Will the person to whom I have given my old smartphone be able to read my WhatsApp messages even though he does not have my SIM card? If so, how do I stop it? Thank you.

 

[B. Diddy]

Welcome to Android Central! Assuming you did a factory reset of the phone prior to giving it to him, and he doesn't know your WhatsApp username and password, then he won't be able to see the messages.