The double acquaintance tick WhatsApp blue is the read receipt symbol. Or, to be more specific, that a specific message has appeared on someone's screen or that someone has marked their notification as read. Whether you have actually read the message or not. And the read receipt, as we know, can be disabled in exchange for not seeing others.
However, if you have them activated and not from your contacts, no, although you will not be able to know if they have read all of your messages, you do have methods to know if you have read some of them. A good WhatsApp trick.
There are two methods to find out if people with disabled read receipts are reading our messages
Messages in group chats
It's no secret that even though a person disables read receipts, they only apply to individual chats: the double tick blue keeps popping up in group chats. This way, therefore, becomes one of the methods to know if a contact has had on his screen the messages that we have sent to a WhatsApp group that we share with him.
WhatsApp has always advised that deactivating read receipts does not apply to group chats
To check who has read our messages in a group, we have several options: do it from the mobile as explained by our colleagues from Engadget Mobile or do it from the WhatsApp applications for PC or macOS or WhatsApp Web as we now explain.
Just go to your own message that we have sent, hover over it and click the down arrow in the upper right. A menu will open in which we will have to choose the option Message info and in the panel that will open we will be able to see which members of the group have read the message and which ones have simply received it on their devices.
Although WhatsApp notifies those who deactivate read receipts that this fact does not affect the groups and that the confirmations will continue to be sent, it does not say anything that they do not affect the audios they receive either. Why no, read receipts do not apply in this case and double check blue appears in chats between two people.
If a contact with deactivated confirmations listens to one of our audios, it will show the double blue 'check'
To check if a contact with deactivated confirmations is reading us, it would be enough to send an audio and wait. If the other person plays it, the audio will show the read receipt and we can know who has entered our conversation. It is not a very practical way, but it can be useful.
In any case, We must be aware that they are not infallible methods and that we must respect the decision of not wanting to inform about the reading or not of the messages. In addition, there are various methods to read messages without appearing as read, as well as listening to audio, for example, so sometimes the methods described can be even more limited and nobody assures us that they have not been read or vice versa.