Sir please bring the option to LOCK specific conversation, NOT like thatuseless PRIVATE BOX present in other messaging apps. The option should lockthe conversation with FOUR digit PIN, so whenever we tap on conversation,it should ask for PIN, and this option SHOULD NOT ENCRYPT the messages sothat other messaging apps will be able to READ MESSAGES of LOCKEDconversation. And it would be more useful of you allow a brief exit time,like if we tap again on conversation in specified period of time, we don'thave to give PIN, for example if we open conversation again in 30 secs.Please bring it in next update, please please.