What does “Locked Messages” mean?

Question

When I try to delete a message, I get prompted to select whether to "Delete locked messages".

There doesn't appear to be any difference if I check this option or leave it unchecked.

Does anyone know what that means?

Answer 1

You can lock a particular message in your conversation so you don't accidentally delete that. The check box is for those messages. See following screen-shots -

1. First Long tap on the message you want to lock, and select Lock.
2. The message should be now locked and a lock icon should appear at the bottom.
3. Now when you delete the conversation the message was in, the locked message would not get deleted if the check-box is not selected.

Answer 2

You can lock messages that you want to retain in your phone. IIRC long pressing the message will give you the option to lock the message.